API Documentation

Pact Python V3.

This package provides contract testing capabilities for Python applications using the Pact specification. Built on the Pact Rust FFI library, it offers full support for all Pact features and maintains compatibility with other Pact implementations.

Package Structure

Main Classes

The primary entry points for contract testing are:

• Pact: For consumer-side contract testing, defining expected interactions and generating contract files.
• Verifier: For provider-side contract verification, validating that a provider implementation satisfies consumer contracts.

These functions are defined in pact.pact and pact.verifier and re-exported for convenience.

Matching and Generation

For flexible contract definitions, use the matching and generation modules:

from pact import match, generate

# Import modules, not individual functions
# Use functions via module namespace to avoid shadowing built-ins
user_id = match.int(min=1)
user_name = match.str(size=20)
created_at = match.datetime()

# Generators work similarly
response_id = generate.uuid()
score = generate.float(precision=2)

The functions within these modules are designed to align with a number of Python built-in types and functions. As such, the module should be imported as a whole, rather than importing individual functions to avoid potential shadowing of built-ins.

Utility Modules

• error: Exception classes used throughout the package. Typically not imported directly unless implementing custom error handling.
• types: Type definitions and protocols. This does not provide much functionality, but will be used by your type-checker.

Basic Usage

Consumer Testing

from pact import Pact, match

# Create a consumer contract
pact = Pact("consumer", "provider")

# Define expected interactions
(
    pact.upon_receiving("get user")
    .given("user exists")
    .with_request(method="GET", path="/users/123")
    .will_respond_with(
        status=200,
        body={
            "id": match.int(123),
            "name": match.str("alice"),
        },
    )
)

# Use in tests with the mock server
with pact.serve() as server:
    # Make requests to server.url
    # Test your consumer code
    pass

Provider Verification

from pact import Verifier

# Verify provider against contracts
verifier = Verifier()
verifier.verify_with_broker(
    provider="provider-name",
    broker_url="https://my-org.pactflow.io",
)

For more detailed usage examples, see the examples.

Classes

Pact(consumer: str, provider: str)

A Pact between a consumer and a provider.

This class defines a Pact between a consumer and a provider. It is the central class in Pact's framework, and is responsible for defining the interactions between the two parties.

One Pact instance should be created for each provider that a consumer interacts with. The methods on this class are used to define the broader attributes of the Pact, such as the consumer and provider names, the Pact specification, any plugins that are used, and any metadata that is attached to the Pact.

Each interaction between the consumer and the provider is defined through the upon_receiving method, which returns a sub-class of Interaction.

PARAMETER	DESCRIPTION
consumer	Name of the consumer. TYPE: str
provider	Name of the provider. TYPE: str

RAISES	DESCRIPTION
ValueError	If the consumer or provider name is empty.

Source code in src/pact/pact.py

def __init__(
    self,
    consumer: str,
    provider: str,
) -> None:
    """
    Initialise a new Pact.

    Args:
        consumer:
            Name of the consumer.

        provider:
            Name of the provider.

    Raises:
        ValueError:
            If the consumer or provider name is empty.
    """
    if not consumer:
        msg = "Consumer name cannot be empty."
        raise ValueError(msg)
    if not provider:
        msg = "Provider name cannot be empty."
        raise ValueError(msg)

    self._consumer = consumer
    self._provider = provider
    self._interactions: set[Interaction] = set()
    self._handle: pact_ffi.PactHandle = pact_ffi.new_pact(
        consumer,
        provider,
    )

Attributes

consumer: str property

Consumer name.

provider: str property

Provider name.

specification: pact_ffi.PactSpecification property

Pact specification version.

Functions

interactions(kind: Literal['HTTP', 'Sync', 'Async'] = 'HTTP') -> Generator[pact_ffi.SynchronousHttp, None, None] | Generator[pact_ffi.SynchronousMessage, None, None] | Generator[pact_ffi.AsynchronousMessage, None, None]

interactions(
    kind: Literal["HTTP"],
) -> Generator[pact_ffi.SynchronousHttp, None, None]

interactions(
    kind: Literal["Sync"],
) -> Generator[pact_ffi.SynchronousMessage, None, None]

interactions(
    kind: Literal["Async"],
) -> Generator[pact_ffi.AsynchronousMessage, None, None]

Return an iterator over the Pact's interactions.

The kind is used to specify the type of interactions that will be iterated over.

RAISES	DESCRIPTION
ValueError	If the kind is unknown.

Source code in src/pact/pact.py

def interactions(
    self,
    kind: Literal["HTTP", "Sync", "Async"] = "HTTP",
) -> (
    Generator[pact_ffi.SynchronousHttp, None, None]
    | Generator[pact_ffi.SynchronousMessage, None, None]
    | Generator[pact_ffi.AsynchronousMessage, None, None]
):
    """
    Return an iterator over the Pact's interactions.

    The kind is used to specify the type of interactions that will be
    iterated over.

    Raises:
        ValueError:
            If the kind is unknown.
    """
    # TODO: Add an iterator for `All` interactions.
    # https://github.com/pact-foundation/pact-python/issues/451
    if kind == "HTTP":
        yield from pact_ffi.pact_handle_get_sync_http_iter(self._handle)
    elif kind == "Sync":
        yield from pact_ffi.pact_handle_get_sync_message_iter(self._handle)
    elif kind == "Async":
        yield from pact_ffi.pact_handle_get_async_message_iter(self._handle)
    else:
        msg = f"Unknown interaction type: {kind}"
        raise ValueError(msg)
    return  # Ensures that the parent object outlives the generator

serve(addr: str = 'localhost', port: int = 0, transport: str = 'http', transport_config: str | None = None, *, raises: bool = True, verbose: bool = True) -> PactServer

Return a mock server for the Pact.

This function configures a mock server for the Pact. The mock server is then started when the Pact is entered into a with block:

pact = Pact("consumer", "provider")
with pact.serve() as srv:
    ...

PARAMETER	DESCRIPTION
addr	Address to bind the mock server to. Defaults to localhost. TYPE: str DEFAULT: 'localhost'
port	Port to bind the mock server to. Defaults to 0, which will select a random port. TYPE: int DEFAULT: 0
transport	Transport to use for the mock server. Defaults to HTTP. TYPE: str DEFAULT: 'http'
transport_config	Configuration for the transport. This is specific to the transport being used and should be a JSON string. TYPE: str | None DEFAULT: None
raises	Whether to raise an exception if there are mismatches between the Pact and the server. If set to False, then the mismatches must be handled manually. TYPE: bool DEFAULT: True
verbose	Whether or not to print the mismatches to the logger. This works independently of raises. TYPE: bool DEFAULT: True

RETURNS	DESCRIPTION
PactServer	PactServer instance.

Source code in src/pact/pact.py

def serve(  # noqa: PLR0913
    self,
    addr: str = "localhost",
    port: int = 0,
    transport: str = "http",
    transport_config: str | None = None,
    *,
    raises: bool = True,
    verbose: bool = True,
) -> PactServer:
    """
    Return a mock server for the Pact.

    This function configures a mock server for the Pact. The mock server
    is then started when the Pact is entered into a `with` block:

    ```python
    pact = Pact("consumer", "provider")
    with pact.serve() as srv:
        ...
    ```

    Args:
        addr:
            Address to bind the mock server to. Defaults to `localhost`.

        port:
            Port to bind the mock server to. Defaults to `0`, which will
            select a random port.

        transport:
            Transport to use for the mock server. Defaults to `HTTP`.

        transport_config:
            Configuration for the transport. This is specific to the
            transport being used and should be a JSON string.

        raises:
            Whether to raise an exception if there are mismatches between
            the Pact and the server. If set to `False`, then the mismatches
            must be handled manually.

        verbose:
            Whether or not to print the mismatches to the logger. This works
            independently of `raises`.

    Returns:
        PactServer instance.
    """
    return PactServer(
        self._handle,
        addr,
        port,
        transport,
        transport_config,
        raises=raises,
        verbose=verbose,
    )

upon_receiving(description: str, interaction: Literal['HTTP', 'Sync', 'Async'] = 'HTTP') -> HttpInteraction | AsyncMessageInteraction | SyncMessageInteraction

upon_receiving(
    description: str, interaction: Literal["HTTP"] = ...
) -> HttpInteraction

upon_receiving(
    description: str, interaction: Literal["Async"]
) -> AsyncMessageInteraction

upon_receiving(
    description: str, interaction: Literal["Sync"]
) -> SyncMessageInteraction

Create a new Interaction.

PARAMETER	DESCRIPTION
description	Description of the interaction. This must be unique within the Pact. TYPE: str
interaction	Type of interaction. Defaults to HTTP. This must be one of HTTP, Async, or Sync. TYPE: Literal['HTTP', 'Sync', 'Async'] DEFAULT: 'HTTP'

RAISES	DESCRIPTION
ValueError	If the interaction type is invalid.

Source code in src/pact/pact.py

def upon_receiving(
    self,
    description: str,
    interaction: Literal["HTTP", "Sync", "Async"] = "HTTP",
) -> HttpInteraction | AsyncMessageInteraction | SyncMessageInteraction:
    """
    Create a new Interaction.

    Args:
        description:
            Description of the interaction. This must be unique
            within the Pact.

        interaction:
            Type of interaction. Defaults to `HTTP`. This must be one of
            `HTTP`, `Async`, or `Sync`.

    Raises:
        ValueError:
            If the interaction type is invalid.
    """
    if interaction == "HTTP":
        return HttpInteraction(self._handle, description)
    if interaction == "Async":
        return AsyncMessageInteraction(self._handle, description)
    if interaction == "Sync":
        return SyncMessageInteraction(self._handle, description)

    msg = f"Invalid interaction type: {interaction}"
    raise ValueError(msg)

using_plugin(name: str, version: str | None = None) -> Self

Add a plugin to be used by the test.

Plugins extend the functionality of Pact.

PARAMETER	DESCRIPTION
name	Name of the plugin. TYPE: str
version	Version of the plugin. This is optional and can be None. TYPE: str | None DEFAULT: None

Source code in src/pact/pact.py

def using_plugin(self, name: str, version: str | None = None) -> Self:
    """
    Add a plugin to be used by the test.

    Plugins extend the functionality of Pact.

    Args:
        name:
            Name of the plugin.

        version:
            Version of the plugin. This is optional and can be `None`.
    """
    pact_ffi.using_plugin(self._handle, name, version)
    return self

verify(handler: Callable[[str | bytes | None, dict[str, object]], None], kind: Literal['Async', 'Sync'], *, raises: bool = True) -> list[InteractionVerificationError] | None

verify(
    handler: Callable[
        [str | bytes | None, dict[str, object]], None
    ],
    kind: Literal["Async", "Sync"],
    *,
    raises: Literal[True] = True,
) -> None

verify(
    handler: Callable[
        [str | bytes | None, dict[str, object]], None
    ],
    kind: Literal["Async", "Sync"],
    *,
    raises: Literal[False],
) -> list[InteractionVerificationError]

Verify message interactions.

This function is used to ensure that the consumer is able to handle the messages that are defined in the Pact. The handler function is called for each message in the Pact.

The end-user is responsible for defining the handler function and verifying that the messages are handled correctly. For example, if the handler is meant to call an API, then the API call should be mocked out and once the verification is complete, the mock should be verified. Any exceptions raised by the handler will be caught and reported as mismatches.

PARAMETER	DESCRIPTION
handler	The function that will be called for each message in the Pact. The first argument to the function is the message body, either as a string or byte array. The second argument is the metadata for the message. If there is no metadata, then this will be an empty dictionary. TYPE: Callable[[str | bytes | None, dict[str, object]], None]
kind	The type of message interaction. This must be one of Async or Sync. TYPE: Literal['Async', 'Sync']
raises	Whether or not to raise an exception if the handler fails to process a message. If set to False, then the function will return a list of errors. TYPE: bool DEFAULT: True

RETURNS	DESCRIPTION
list[InteractionVerificationError] | None	None if raises is True and no errors occurred, otherwise a list of
list[InteractionVerificationError] | None	InteractionVerificationError.

RAISES	DESCRIPTION
TypeError	If the message type is unknown.
PactVerificationError	If raises is True and there are errors.

Source code in src/pact/pact.py

def verify(
    self,
    handler: Callable[[str | bytes | None, dict[str, object]], None],
    kind: Literal["Async", "Sync"],
    *,
    raises: bool = True,
) -> list[InteractionVerificationError] | None:
    """
    Verify message interactions.

    This function is used to ensure that the consumer is able to handle the
    messages that are defined in the Pact. The `handler` function is called
    for each message in the Pact.

    The end-user is responsible for defining the `handler` function and
    verifying that the messages are handled correctly. For example, if the
    handler is meant to call an API, then the API call should be mocked out
    and once the verification is complete, the mock should be verified. Any
    exceptions raised by the handler will be caught and reported as
    mismatches.

    Args:
        handler:
            The function that will be called for each message in the Pact.

            The first argument to the function is the message body, either as
            a string or byte array.

            The second argument is the metadata for the message. If there
            is no metadata, then this will be an empty dictionary.

        kind:
            The type of message interaction. This must be one of `Async`
            or `Sync`.

        raises:
            Whether or not to raise an exception if the handler fails to
            process a message. If set to `False`, then the function will
            return a list of errors.

    Returns:
        `None` if raises is True and no errors occurred, otherwise a list of
        [`InteractionVerificationError`][pact.error.InteractionVerificationError].

    Raises:
        TypeError:
            If the message type is unknown.

        PactVerificationError:
            If raises is True and there are errors.
    """
    errors: list[InteractionVerificationError] = []
    for message in self.interactions(kind):
        request: pact_ffi.MessageContents | None = None
        if isinstance(message, pact_ffi.SynchronousMessage):
            request = message.request_contents
        elif isinstance(message, pact_ffi.AsynchronousMessage):
            request = message.contents
        else:
            msg = f"Unknown message type: {type(message).__name__}"
            raise TypeError(msg)

        if request is None:
            warnings.warn(
                f"Message '{message.description}' has no contents",
                stacklevel=2,
            )
            continue

        body = request.contents
        metadata: dict[str, object] = {}
        for pair in request.metadata:
            try:
                v = json.loads(pair.value)
            except json.JSONDecodeError:
                v = pair.value
            metadata[pair.key] = v

        try:
            handler(body, metadata)
        except Exception as e:  # noqa: BLE001
            errors.append(InteractionVerificationError(message.description, e))

    if raises:
        if errors:
            raise PactVerificationError(errors)
        return None
    return errors

with_metadata(namespace: str, metadata: dict[str, str]) -> Self

Set additional metadata for the Pact.

A common use for this function is to add information about the client library (name, version, hash, etc.) to the Pact.

PARAMETER	DESCRIPTION
namespace	Namespace for the metadata. This is used to group the metadata together. TYPE: str
metadata	Key-value pairs of metadata to add to the Pact. TYPE: dict[str, str]

Source code in src/pact/pact.py

def with_metadata(
    self,
    namespace: str,
    metadata: dict[str, str],
) -> Self:
    """
    Set additional metadata for the Pact.

    A common use for this function is to add information about the client
    library (name, version, hash, etc.) to the Pact.

    Args:
        namespace:
            Namespace for the metadata. This is used to group the metadata
            together.

        metadata:
            Key-value pairs of metadata to add to the Pact.
    """
    for k, v in metadata.items():
        pact_ffi.with_pact_metadata(self._handle, namespace, k, v)
    return self

with_specification(version: str | pact_ffi.PactSpecification) -> Self

Set the Pact specification version.

The Pact specification version indicates the features which are supported by the Pact, and certain default behaviours.

PARAMETER	DESCRIPTION
version	Pact specification version. This can be either a string or a PactSpecification instance. The version string is case insensitive and has an optional v prefix. TYPE: str | PactSpecification

Source code in src/pact/pact.py

def with_specification(
    self,
    version: str | pact_ffi.PactSpecification,
) -> Self:
    """
    Set the Pact specification version.

    The Pact specification version indicates the features which are
    supported by the Pact, and certain default behaviours.

    Args:
        version:
            Pact specification version. This can be either a string or a
            [`PactSpecification`][pact_ffi.PactSpecification] instance.

            The version string is case insensitive and has an optional `v`
            prefix.
    """
    if isinstance(version, str):
        version = pact_ffi.PactSpecification.from_str(version)
    pact_ffi.with_specification(self._handle, version)
    return self

write_file(directory: Path | str | None = None, *, overwrite: bool = False) -> None

Write out the pact to a file.

This function should be called once all of the consumer tests have been run. It writes the Pact to a file, which can then be used to validate the provider.

PARAMETER	DESCRIPTION
directory	The directory to write the pact to. If the directory does not exist, it will be created. The filename will be automatically generated from the underlying Pact. TYPE: Path | str | None DEFAULT: None
overwrite	If set to True, the file will be overwritten if it already exists. Otherwise, the contents of the file will be merged with the existing file. TYPE: bool DEFAULT: False

Source code in src/pact/pact.py

def write_file(
    self,
    directory: Path | str | None = None,
    *,
    overwrite: bool = False,
) -> None:
    """
    Write out the pact to a file.

    This function should be called once all of the consumer tests have been
    run. It writes the Pact to a file, which can then be used to validate
    the provider.

    Args:
        directory:
            The directory to write the pact to. If the directory does not
            exist, it will be created. The filename will be
            automatically generated from the underlying Pact.

        overwrite:
            If set to True, the file will be overwritten if it already
            exists. Otherwise, the contents of the file will be merged with
            the existing file.
    """
    if directory is None:
        directory = Path.cwd()
    pact_ffi.pact_handle_write_file(
        self._handle,
        directory,
        overwrite=overwrite,
    )

Verifier(name: str, host: str | None = None)

A Verifier between a consumer and a provider.

This class encapsulates the logic for verifying that a provider meets the expectations of a consumer. This is done by replaying interactions from the consumer against the provider, and ensuring that the provider's responses match the expectations set by the consumer.

PARAMETER	DESCRIPTION
name	The name of the provider to verify. This is used to identify which interactions the provider is involved in, and then Pact will replay these interactions against the provider. TYPE: str
host	The host on which the Pact verifier is running. This is used to communicate with the provider. If not specified, the default value is localhost. TYPE: str | None DEFAULT: None

Source code in src/pact/verifier.py

def __init__(self, name: str, host: str | None = None) -> None:
    """
    Create a new Verifier.

    Args:
        name:
            The name of the provider to verify. This is used to identify
            which interactions the provider is involved in, and then Pact
            will replay these interactions against the provider.

        host:
            The host on which the Pact verifier is running. This is used to
            communicate with the provider. If not specified, the default
            value is `localhost`.
    """
    self._name = name
    self._host = host or "localhost"
    self._handle = pact_ffi.verifier_new_for_application()
    self._branch: str | None = None

    # In order to provide a fluent interface, we remember some options which
    # are set using the same FFI method. In particular, we remember
    # transport methods defined, and then before verification call the
    # `set_info` and `add_transport` FFI methods as needed.
    self._transports: list[_ProviderTransport] = []
    self._message_producer: (
        MessageProducer[Callable[..., Message]] | nullcontext[None]
    ) = nullcontext()
    self._state_handler: StateCallback[Callable[..., None]] | nullcontext[None] = (
        nullcontext()
    )
    self._disable_ssl_verification = False
    self._request_timeout = 5000
    # Using a broker source requires knowing the provider name, which is
    # only provided to the FFI just before verification. As such, we store
    # the broker source as a hook to be called just before verification, and
    # after the provider name is set.
    self._broker_source_hook: Callable[[], None] | None = None

Attributes

logs: str property

Get the logs.

results: dict[str, Any] property

Get the results.

Functions

add_custom_header(name: str, value: str) -> Self

Add a customer header to the request.

These headers are added to every request made to the provider.

PARAMETER	DESCRIPTION
name	The key of the header. TYPE: str
value	The value of the header. TYPE: str

Source code in src/pact/verifier.py

def add_custom_header(self, name: str, value: str) -> Self:
    """
    Add a customer header to the request.

    These headers are added to every request made to the provider.

    Args:
        name:
            The key of the header.

        value:
            The value of the header.
    """
    pact_ffi.verifier_add_custom_header(self._handle, name, value)
    return self

add_custom_headers(headers: dict[str, str] | Iterable[tuple[str, str]]) -> Self

Add multiple customer headers to the request.

These headers are added to every request made to the provider.

PARAMETER	DESCRIPTION
headers	The headers to add. The value can be: - a dictionary of header key-value pairs - an iterable of (key, value) tuples TYPE: dict[str, str] | Iterable[tuple[str, str]]

Source code in src/pact/verifier.py

def add_custom_headers(
    self,
    headers: dict[str, str] | Iterable[tuple[str, str]],
) -> Self:
    """
    Add multiple customer headers to the request.

    These headers are added to every request made to the provider.

    Args:
        headers:
            The headers to add.

            The value can be:
                - a dictionary of header key-value pairs
                - an iterable of (key, value) tuples
    """
    if isinstance(headers, dict):
        headers = headers.items()
    for name, value in headers:
        self.add_custom_header(name, value)
    return self

add_source(source: str | Path | URL, *, username: str | None = None, password: str | None = None, token: str | None = None) -> Self

add_source(
    source: str | URL,
    *,
    username: str | None = None,
    password: str | None = None,
) -> Self

add_source(
    source: str | URL, *, token: str | None = None
) -> Self

add_source(source: str | Path) -> Self

Adds a source to the verifier.

This will use one or more Pact files as the source of interactions to verify.

PARAMETER	DESCRIPTION
source	The source of the interactions. This may be either of the following: A local file path to a Pact file. A local file path to a directory containing Pact files. A URL to a Pact file. If using a URL, the username and password parameters can be used to provide basic HTTP authentication, or the token parameter can be used to provide bearer token authentication. The username and password parameters can also be passed as part of the URL. TYPE: str | Path | URL
username	The username to use for basic HTTP authentication. This is only used when the source is a URL. TYPE: str | None DEFAULT: None
password	The password to use for basic HTTP authentication. This is only used when the source is a URL. TYPE: str | None DEFAULT: None
token	The token to use for bearer token authentication. This is only used when the source is a URL. Note that this is mutually exclusive with username and password. TYPE: str | None DEFAULT: None

RAISES	DESCRIPTION
ValueError	If the source scheme is invalid.

Source code in src/pact/verifier.py

def add_source(
    self,
    source: str | Path | URL,
    *,
    username: str | None = None,
    password: str | None = None,
    token: str | None = None,
) -> Self:
    """
    Adds a source to the verifier.

    This will use one or more Pact files as the source of interactions to
    verify.

    Args:
        source:
            The source of the interactions. This may be either of the following:

            -   A local file path to a Pact file.
            -   A local file path to a directory containing Pact files.
            -   A URL to a Pact file.

            If using a URL, the `username` and `password` parameters can be
            used to provide basic HTTP authentication, or the `token`
            parameter can be used to provide bearer token authentication.
            The `username` and `password` parameters can also be passed as
            part of the URL.

        username:
            The username to use for basic HTTP authentication. This is only
            used when the source is a URL.

        password:
            The password to use for basic HTTP authentication. This is only
            used when the source is a URL.

        token:
            The token to use for bearer token authentication. This is only
            used when the source is a URL. Note that this is mutually
            exclusive with `username` and `password`.

    Raises:
        ValueError:
            If the source scheme is invalid.
    """
    if isinstance(source, Path):
        return self._add_source_local(source)

    if isinstance(source, URL):
        if source.scheme == "file":
            return self._add_source_local(source.path)

        if source.scheme in ("http", "https"):
            return self._add_source_remote(
                source,
                username=username,
                password=password,
                token=token,
            )

        msg = f"Invalid source scheme: {source.scheme}"
        raise ValueError(msg)

    # Strings are ambiguous, so we need identify them as either local or
    # remote.
    if "://" in source:
        return self._add_source_remote(
            URL(source),
            username=username,
            password=password,
            token=token,
        )
    return self._add_source_local(source)

add_transport(*, url: str | URL | None = None, protocol: str | None = None, port: int | None = None, path: str | None = None, scheme: str | None = None) -> Self

Add a provider transport method.

If the provider supports multiple transport methods, or non-HTTP(S) methods, this method allows these additional transport methods to be added. It can be called multiple times to add multiple transport methods.

As some transport methods may not use ports, paths or schemes, these parameters are optional. Note that while optional, these may still be used during testing as Pact uses HTTP(S) to communicate with the provider. For example, if you are implementing your own message verification, it needs to be exposed over HTTP and the port and path arguments are used for this testing communication.

PARAMETER	DESCRIPTION
url	A convenient way to set the provider transport. This option is mutually exclusive with the other options. TYPE: str | URL | None DEFAULT: None
protocol	The protocol to use. This will typically be one of: http for communications over HTTP(S) message for non-plugin message-based communications Any other protocol will be treated as a custom protocol and will be handled by a plugin. If url is not specified, this parameter is required. TYPE: str | None DEFAULT: None
port	The provider port. If the protocol does not use ports, this parameter should be None. If not specified, the default port for the scheme will be used (provided the scheme is known). TYPE: int | None DEFAULT: None
path	The provider context path. For protocols which do not use paths, this parameter should be None. For protocols which do use paths, this parameter should be specified to avoid any ambiguity, though if left unspecified, the root path will be used. If a non-root path is used, the path given here will be prepended to the path in the interaction. For example, if the path is /api, and the interaction path is /users, the request will be made to /api/users. TYPE: str | None DEFAULT: None
scheme	The provider scheme, if applicable to the protocol. This is typically only used for the http protocol, where this value can either be http (the default) or https. TYPE: str | None DEFAULT: None

RAISES	DESCRIPTION
ValueError	If mutually exclusive parameters are provided, or required parameters are missing, or host/protocol mismatches.

Source code in src/pact/verifier.py

def add_transport(
    self,
    *,
    url: str | URL | None = None,
    protocol: str | None = None,
    port: int | None = None,
    path: str | None = None,
    scheme: str | None = None,
) -> Self:
    """
    Add a provider transport method.

    If the provider supports multiple transport methods, or non-HTTP(S)
    methods, this method allows these additional transport methods to be
    added. It can be called multiple times to add multiple transport
    methods.

    As some transport methods may not use ports, paths or schemes, these
    parameters are optional. Note that while optional, these _may_ still be
    used during testing as Pact uses HTTP(S) to communicate with the
    provider. For example, if you are implementing your own message
    verification, it needs to be exposed over HTTP and the `port` and `path`
    arguments are used for this testing communication.

    Args:
        url:
            A convenient way to set the provider transport. This option
            is mutually exclusive with the other options.

        protocol:
            The protocol to use. This will typically be one of:

            -   `http` for communications over HTTP(S)

            -   `message` for non-plugin message-based communications

            Any other protocol will be treated as a custom protocol and will
            be handled by a plugin.

            If `url` is _not_ specified, this parameter is required.

        port:
            The provider port.

            If the protocol does not use ports, this parameter should be
            `None`. If not specified, the default port for the scheme will
            be used (provided the scheme is known).

        path:
            The provider context path.

            For protocols which do not use paths, this parameter should be
            `None`.

            For protocols which do use paths, this parameter should be
            specified to avoid any ambiguity, though if left unspecified,
            the root path will be used.

            If a non-root path is used, the path given here will be
            prepended to the path in the interaction. For example, if the
            path is `/api`, and the interaction path is `/users`, the
            request will be made to `/api/users`.

        scheme:
            The provider scheme, if applicable to the protocol.

            This is typically only used for the `http` protocol, where this
            value can either be `http` (the default) or `https`.

    Raises:
        ValueError:
            If mutually exclusive parameters are provided, or required
            parameters are missing, or host/protocol mismatches.
    """
    if url and any(x is not None for x in (protocol, port, path, scheme)):
        msg = "The `url` parameter is mutually exclusive with other parameters"
        raise ValueError(msg)

    if url:
        url = URL(url)
        if url.host != self._host:
            msg = f"Host mismatch: {url.host} != {self._host}"
            raise ValueError(msg)
        protocol = url.scheme
        if protocol == "https":
            protocol = "http"
        port = url.port
        path = url.path
        scheme = url.scheme
        return self.add_transport(
            protocol=protocol,
            port=port,
            path=path,
            scheme=scheme,
        )

    if not protocol:
        msg = "A protocol must be specified"
        raise ValueError(msg)

    if port is None and scheme:
        if scheme.lower() == "http":
            port = 80
        elif scheme.lower() == "https":
            port = 443

    logger.debug(
        "Adding transport to verifier",
        extra={
            "protocol": protocol,
            "port": port,
            "path": path,
            "scheme": scheme,
        },
    )
    self._transports.append(
        _ProviderTransport(
            transport=protocol,
            port=port,
            path=path,
            scheme=scheme,
        )
    )

    return self

broker_source(url: str | URL, *, username: str | None = None, password: str | None = None, token: str | None = None, selector: bool = False) -> BrokerSelectorBuilder | Self

broker_source(
    url: str | URL,
    *,
    username: str | None = None,
    password: str | None = None,
    selector: Literal[False] = False,
) -> Self

broker_source(
    url: str | URL,
    *,
    token: str | None = None,
    selector: Literal[False] = False,
) -> Self

broker_source(
    url: str | URL,
    *,
    username: str | None = None,
    password: str | None = None,
    selector: Literal[True],
) -> BrokerSelectorBuilder

broker_source(
    url: str | URL,
    *,
    token: str | None = None,
    selector: Literal[True],
) -> BrokerSelectorBuilder

Adds a broker source to the verifier.

PARAMETER	DESCRIPTION
url	The broker URL. The URL may contain a username and password for basic HTTP authentication. TYPE: str | URL
username	The username to use for basic HTTP authentication. If the source is a URL containing a username, this parameter must be None. TYPE: str | None DEFAULT: None
password	The password to use for basic HTTP authentication. If the source is a URL containing a password, this parameter must be None. TYPE: str | None DEFAULT: None
token	The token to use for bearer token authentication. This is mutually exclusive with username and password (whether they be specified through arguments, or embedded in the URL). TYPE: str | None DEFAULT: None
selector	Whether to return a BrokerSelectorBuilder instance. TYPE: bool DEFAULT: False

RAISES	DESCRIPTION
ValueError	If mutually exclusive authentication parameters are provided.

Source code in src/pact/verifier.py

def broker_source(
    self,
    url: str | URL,
    *,
    username: str | None = None,
    password: str | None = None,
    token: str | None = None,
    selector: bool = False,
) -> BrokerSelectorBuilder | Self:
    """
    Adds a broker source to the verifier.

    Args:
        url:
            The broker URL. The URL may contain a username and password for
            basic HTTP authentication.

        username:
            The username to use for basic HTTP authentication. If the source
            is a URL containing a username, this parameter must be `None`.

        password:
            The password to use for basic HTTP authentication. If the source
            is a URL containing a password, this parameter must be `None`.

        token:
            The token to use for bearer token authentication. This is
            mutually exclusive with `username` and `password` (whether they
            be specified through arguments, or embedded in the URL).

        selector:
            Whether to return a BrokerSelectorBuilder instance.

    Raises:
        ValueError:
            If mutually exclusive authentication parameters are provided.
    """
    url = URL(url)

    if url.user and username:
        msg = "Cannot specify both `username` and a username in the URL"
        raise ValueError(msg)
    username = url.user or username

    if url.password and password:
        msg = "Cannot specify both `password` and a password in the URL"
        raise ValueError(msg)
    password = url.password or password

    if token and (username or password):
        msg = "Cannot specify both `token` and `username`/`password`"
        raise ValueError(msg)

    if selector:
        return BrokerSelectorBuilder(
            self,
            str(url.with_user(None).with_password(None)),
            username,
            password,
            token,
        )

    self._broker_source_hook = lambda: pact_ffi.verifier_broker_source(
        self._handle,
        str(url.with_user(None).with_password(None)),
        username,
        password,
        token,
    )

    return self

disable_ssl_verification() -> Self

Disable SSL verification.

Source code in src/pact/verifier.py

def disable_ssl_verification(self) -> Self:
    """
    Disable SSL verification.
    """
    self._disable_ssl_verification = True
    pact_ffi.verifier_set_verification_options(
        self._handle,
        disable_ssl_verification=self._disable_ssl_verification,
        request_timeout=self._request_timeout,
    )
    return self

filter(description: str | None = None, *, state: str | None = None, no_state: bool = False) -> Self

Set the filter for the interactions.

This method can be used to filter interactions based on their description and state. Repeated calls to this method will replace the previous filter.

PARAMETER	DESCRIPTION
description	The interaction description. This should be a regular expression. If unspecified, no filtering will be done based on the description. TYPE: str | None DEFAULT: None
state	The interaction state. This should be a regular expression. If unspecified, no filtering will be done based on the state. TYPE: str | None DEFAULT: None
no_state	Whether to include interactions with no state. TYPE: bool DEFAULT: False

Source code in src/pact/verifier.py

def filter(
    self,
    description: str | None = None,
    *,
    state: str | None = None,
    no_state: bool = False,
) -> Self:
    """
    Set the filter for the interactions.

    This method can be used to filter interactions based on their
    description and state. Repeated calls to this method will replace the
    previous filter.

    Args:
        description:
            The interaction description.

            This should be a regular expression. If unspecified, no
            filtering will be done based on the description.

        state:
            The interaction state.

            This should be a regular expression. If unspecified, no
            filtering will be done based on the state.

        no_state:
            Whether to include interactions with no state.
    """
    logger.debug(
        "Setting filter for verifier",
        extra={
            "description": description,
            "state": state,
            "no_state": no_state,
        },
    )
    pact_ffi.verifier_set_filter_info(
        self._handle,
        description,
        state,
        filter_no_state=no_state,
    )
    return self

filter_consumers(*filters: str) -> Self

Filter the consumers.

PARAMETER	DESCRIPTION
filters	Filters to apply to the consumers. TYPE: str DEFAULT: ()

Source code in src/pact/verifier.py

def filter_consumers(self, *filters: str) -> Self:
    """
    Filter the consumers.

    Args:
        filters:
            Filters to apply to the consumers.
    """
    pact_ffi.verifier_set_consumer_filters(self._handle, filters)
    return self

logs_for_provider(provider: str) -> str classmethod

Get the logs for a provider.

Source code in src/pact/verifier.py

@classmethod
def logs_for_provider(cls, provider: str) -> str:
    """
    Get the logs for a provider.
    """
    return pact_ffi.verifier_logs_for_provider(provider)

message_handler(handler: Callable[..., Message] | dict[str, Callable[..., Message] | Message | bytes]) -> Self

Set the message handler.

This method sets a custom message handler for the verifier. The handler can be called to produce a specific message to send to the provider.

This can be provided in one of two ways:

1. A fully fledged function that will be called for all messages. This is the most powerful option as it allows for full control over the message generation. The function's signature must be compatible with the MessageProducerArgs type.

2. A dictionary mapping message names to either (a) producer functions, (b) Message dictionaries, or © raw bytes. If using a producer function, it must be compatible with the MessageProducerArgs type.

Implementation

There are a large number of ways to send messages, and the specifics of the transport methods are not specifically relevant to Pact. As such, Pact abstracts the transport layer away and uses a lightweight HTTP server to handle messages.

Pact Python is capable of setting up this server and handling the messages internally using user-provided handlers. It is possible to use your own HTTP server to handle messages by using the add_transport method. It is not possible to use both this method and add_transport to handle messages.

PARAMETER	DESCRIPTION
handler	The message handler. This should be a callable or a dictionary mapping message names to callables, Message dicts, or bytes. TYPE: Callable[..., Message] | dict[str, Callable[..., Message] | Message | bytes]

RAISES	DESCRIPTION
TypeError	If the handler or its values are invalid.

Source code in src/pact/verifier.py

def message_handler(
    self,
    handler: Callable[..., Message]
    | dict[str, Callable[..., Message] | Message | bytes],
) -> Self:
    """
    Set the message handler.

    This method sets a custom message handler for the verifier. The handler
    can be called to produce a specific message to send to the provider.

    This can be provided in one of two ways:

    1.  A fully fledged function that will be called for all messages. This
        is the most powerful option as it allows for full control over the
        message generation. The function's signature must be compatible with
        the [`MessageProducerArgs`][pact.types.MessageProducerArgs] type.

    2.  A dictionary mapping message names to either (a) producer functions,
        (b) [`Message`][pact.types.Message] dictionaries, or (c) raw
        bytes. If using a producer function, it must be compatible with the
        [`MessageProducerArgs`][pact.types.MessageProducerArgs] type.

    ## Implementation

    There are a large number of ways to send messages, and the specifics of
    the transport methods are not specifically relevant to Pact. As such,
    Pact abstracts the transport layer away and uses a lightweight HTTP
    server to handle messages.

    Pact Python is capable of setting up this server and handling the
    messages internally using user-provided handlers. It is possible to use
    your own HTTP server to handle messages by using the `add_transport`
    method. It is not possible to use both this method and `add_transport`
    to handle messages.

    Args:
        handler:
            The message handler.

            This should be a callable or a dictionary mapping message names
            to callables, Message dicts, or bytes.

    Raises:
        TypeError:
            If the handler or its values are invalid.
    """
    logger.debug(
        "Setting message handler for verifier",
        extra={
            "path": "/_pact/message",
        },
    )

    if callable(handler):

        def _handler(
            name: str,
            metadata: dict[str, Any] | None,
        ) -> Message:
            logger.info("Internal message produced called.")
            return apply_args(
                handler,
                MessageProducerArgs(name=name, metadata=metadata),
            )

        self._message_producer = MessageProducer(_handler)
        self.add_transport(
            protocol="message",
            port=self._message_producer.port,
            path=self._message_producer.path,
        )
        return self

    if isinstance(handler, dict):

        def _handler(
            name: str,
            metadata: dict[str, Any] | None,
        ) -> Message:
            logger.info("Internal message produced called.")
            val = handler[name]

            if callable(val):
                return apply_args(
                    val,
                    MessageProducerArgs(name=name, metadata=metadata),
                )
            if isinstance(val, bytes):
                return Message(contents=val, metadata=None, content_type=None)
            if isinstance(val, dict):
                return Message(
                    contents=val["contents"],
                    metadata=val.get("metadata"),
                    content_type=val.get("content_type"),
                )

            msg = "Invalid message handler value"
            raise TypeError(msg)

        self._message_producer = MessageProducer(_handler)
        self.add_transport(
            protocol="message",
            port=self._message_producer.port,
            path=self._message_producer.path,
        )

        return self

    msg = "Invalid message handler type"
    raise TypeError(msg)

output(*, strip_ansi: bool = False) -> str

Get the output.

Source code in src/pact/verifier.py

def output(self, *, strip_ansi: bool = False) -> str:
    """
    Get the output.
    """
    return pact_ffi.verifier_output(self._handle, strip_ansi=strip_ansi)

set_coloured_output(*, enabled: bool = True) -> Self

Toggle coloured output.

Source code in src/pact/verifier.py

def set_coloured_output(self, *, enabled: bool = True) -> Self:
    """
    Toggle coloured output.
    """
    pact_ffi.verifier_set_coloured_output(self._handle, enabled=enabled)
    return self

set_error_on_empty_pact(*, enabled: bool = True) -> Self

Toggle error on empty pact.

If enabled, a Pact file with no interactions will cause the verifier to return an error. If disabled, a Pact file with no interactions will be ignored.

Source code in src/pact/verifier.py

def set_error_on_empty_pact(self, *, enabled: bool = True) -> Self:
    """
    Toggle error on empty pact.

    If enabled, a Pact file with no interactions will cause the verifier to
    return an error. If disabled, a Pact file with no interactions will be
    ignored.
    """
    pact_ffi.verifier_set_no_pacts_is_error(self._handle, enabled=enabled)
    return self

set_publish_options(version: str, url: str | None = None, branch: str | None = None, tags: list[str] | None = None) -> Self

Set options used when publishing results to the Broker.

PARAMETER	DESCRIPTION
version	The provider version. TYPE: str
url	URL to the build which ran the verification. TYPE: str | None DEFAULT: None
tags	Collection of tags for the provider. TYPE: list[str] | None DEFAULT: None
branch	Name of the branch used for verification. The first time a branch is set here or through provider_branch, the value will be saved and use as a default for both. TYPE: str | None DEFAULT: None

Source code in src/pact/verifier.py

def set_publish_options(
    self,
    version: str,
    url: str | None = None,
    branch: str | None = None,
    tags: list[str] | None = None,
) -> Self:
    """
    Set options used when publishing results to the Broker.

    Args:
        version:
            The provider version.

        url:
            URL to the build which ran the verification.

        tags:
            Collection of tags for the provider.

        branch:
            Name of the branch used for verification.

            The first time a branch is set here or through
            [`provider_branch`][pact.verifier.BrokerSelectorBuilder.provider_branch],
            the value will be saved and use as a default for both.
    """
    if not self._branch and branch:
        self._branch = branch
    pact_ffi.verifier_set_publish_options(
        self._handle,
        version,
        url,
        tags or [],
        branch or self._branch,
    )
    return self

set_request_timeout(timeout: int) -> Self

Set the request timeout.

PARAMETER	DESCRIPTION
timeout	The request timeout in milliseconds. TYPE: int

RAISES	DESCRIPTION
ValueError	If the timeout is negative.

Source code in src/pact/verifier.py

def set_request_timeout(self, timeout: int) -> Self:
    """
    Set the request timeout.

    Args:
        timeout:
            The request timeout in milliseconds.

    Raises:
        ValueError:
            If the timeout is negative.
    """
    if timeout < 0:
        msg = "Request timeout must be a positive integer"
        raise ValueError(msg)

    self._request_timeout = timeout
    pact_ffi.verifier_set_verification_options(
        self._handle,
        disable_ssl_verification=self._disable_ssl_verification,
        request_timeout=self._request_timeout,
    )
    return self

state_handler(handler: Callable[..., None] | Mapping[str, Callable[..., None]] | StateHandlerUrl, *, teardown: bool = False, body: bool | None = None) -> Self

state_handler(
    handler: Callable[..., None],
    *,
    teardown: bool = False,
    body: None = None,
) -> Self

state_handler(
    handler: Mapping[str, Callable[..., None]],
    *,
    teardown: bool = False,
    body: None = None,
) -> Self

state_handler(
    handler: StateHandlerUrl,
    *,
    teardown: bool = False,
    body: bool,
) -> Self

Set the state handler.

In many interactions, the consumer will assume that the provider is in a certain state. For example, a consumer requesting information about a user with ID 123 will have specified given("user with ID 123 exists").

The state handler is responsible for changing the provider's internal state to match the expected state before the interaction is replayed.

This can be done in one of three ways:

1. By providing a single function that will be called for all state changes.
2. By providing a mapping of state names to functions.
3. By providing the URL endpoint to which the request should be made.

The last option is more complicated as it requires the provider to be able to handle the state change requests. The first two options handle this internally and are the preferred options if the provider is written in Python.

The function signature must be compatible with the StateHandlerArgs. If the function has additional arguments, these must either have default values, or be filled by using the partial function.

Pact also uses a special state denoted with the empty string "". This is used as a generic test setup/teardown handler. This key is optional in dictionaries, but other implementation should ensure they can handle (or safely ignore) this state name.

PARAMETER	DESCRIPTION
handler	The handler for the state changes. This can be one of the following: A single function that will be called for all state changes. A dictionary mapping state names to functions. A URL endpoint to which the request should be made. See above for more information on the function signature. TYPE: Callable[..., None] | Mapping[str, Callable[..., None]] | StateHandlerUrl
teardown	Whether to teardown the provider state after an interaction is validated. TYPE: bool DEFAULT: False
body	Whether to include the state change request in the body (True) or in the query string (False). This must be left as None if providing one or more handler functions; and it must be set to a boolean if providing a URL. TYPE: bool | None DEFAULT: None

RAISES	DESCRIPTION
ValueError	If the handler/body combination is invalid.
TypeError	If the handler type is invalid.

Source code in src/pact/verifier.py

def state_handler(
    self,
    handler: Callable[..., None]
    | Mapping[str, Callable[..., None]]
    | StateHandlerUrl,
    *,
    teardown: bool = False,
    body: bool | None = None,
) -> Self:
    """
    Set the state handler.

    In many interactions, the consumer will assume that the provider is in a
    certain state. For example, a consumer requesting information about a
    user with ID `123` will have specified `given("user with ID 123
    exists")`.

    The state handler is responsible for changing the provider's internal
    state to match the expected state before the interaction is replayed.

    This can be done in one of three ways:

    1.  By providing a single function that will be called for all state
        changes.
    2.  By providing a mapping of state names to functions.
    3.  By providing the URL endpoint to which the request should be made.

    The last option is more complicated as it requires the provider to be
    able to handle the state change requests. The first two options handle
    this internally and are the preferred options if the provider is written
    in Python.

    The function signature must be compatible with the
    [`StateHandlerArgs`][pact.types.StateHandlerArgs]. If the function
    has additional arguments, these must either have default values, or be
    filled by using the [`partial`][functools.partial] function.

    Pact also uses a special state denoted with the empty string `""`. This
    is used as a generic test setup/teardown handler. This key is optional
    in dictionaries, but other implementation should ensure they can handle
    (or safely ignore) this state name.

    Args:
        handler:
            The handler for the state changes. This can be one of the
            following:

            -   A single function that will be called for all state changes.
            -   A dictionary mapping state names to functions.
            -   A URL endpoint to which the request should be made.

            See above for more information on the function signature.

        teardown:
            Whether to teardown the provider state after an interaction is
            validated.

        body:
            Whether to include the state change request in the body (`True`)
            or in the query string (`False`). This must be left as `None` if
            providing one or more handler functions; and it must be set to a
            boolean if providing a URL.

    Raises:
        ValueError:
            If the handler/body combination is invalid.

        TypeError:
            If the handler type is invalid.
    """
    # A tuple is required instead of `StateHandlerUrl` for support for
    # Python 3.9. This should be changed to `StateHandlerUrl` in the future.
    if isinstance(handler, (str, URL)):
        if body is None:
            msg = "The `body` parameter must be a boolean when providing a URL"
            raise ValueError(msg)
        return self._state_handler_url(handler, teardown=teardown, body=body)

    if isinstance(handler, Mapping):
        if body is not None:
            msg = "The `body` parameter must be `None` when providing a dictionary"
            raise ValueError(msg)
        return self._state_handler_dict(handler, teardown=teardown)

    if callable(handler):
        if body is not None:
            msg = "The `body` parameter must be `None` when providing a function"
            raise ValueError(msg)
        return self._state_handler_function(handler, teardown=teardown)

    msg = "Invalid handler type"
    raise TypeError(msg)

verify() -> Self

Verify the interactions.

RETURNS	DESCRIPTION
Self	Whether the interactions were verified successfully.

RAISES	DESCRIPTION
RuntimeError	If no transports have been set.

Source code in src/pact/verifier.py

def verify(self) -> Self:
    """
    Verify the interactions.

    Returns:
        Whether the interactions were verified successfully.

    Raises:
        RuntimeError:
            If no transports have been set.
    """
    if not self._transports:
        msg = "No transports have been set"
        raise RuntimeError(msg)

    first, *rest = self._transports

    pact_ffi.verifier_set_provider_info(
        self._handle,
        self._name,
        first["scheme"],
        self._host,
        first["port"],
        first["path"],
    )

    for transport in rest:
        pact_ffi.verifier_add_provider_transport(
            self._handle,
            transport["transport"],
            transport["port"] or 0,
            transport["path"],
            transport["scheme"],
        )

    if self._broker_source_hook:
        self._broker_source_hook()

    with self._message_producer, self._state_handler:
        pact_ffi.verifier_execute(self._handle)
        logger.debug("Verifier executed")

    return self