chore: Lazily evaluate the vcr_config fixture

src/pytest_recording/plugin.py

@@ -23,9 +23,9 @@ def pytest_configure(config: Config) -> None:
         )
     config.addinivalue_line("markers", "vcr: Mark the test as using VCR.py.")
     config.addinivalue_line("markers", "block_network: Block network access except for VCR recording.")
-    config.addinivalue_line("markers", "default_cassette: Override the default cassette name..")
+    config.addinivalue_line("markers", "default_cassette: Override the default cassette name.")
     config.addinivalue_line(
-        "markers", "allowed_hosts: List of regexes to match hosts to where connection must be allowed"
+        "markers", "allowed_hosts: List of regexes to match hosts to where connection must be allowed."
     )
     network.install_pycurl_wrapper()
 
@@ -83,41 +83,49 @@ def vcr_config() -> Dict:
 
 
 @pytest.fixture  # type: ignore
-def vcr_markers(request: SubRequest) -> List[Mark]:
-    """All markers applied to the certain test together with cassette names associated with each marker."""
-    return list(request.node.iter_markers(name="vcr"))
-
-
-@pytest.fixture(autouse=True)  # type: ignore
-def block_network(request: SubRequest, record_mode: str, vcr_markers: List[Mark]) -> Iterator[None]:
-    """Block network access in tests except for "none" VCR recording mode."""
-    marker = request.node.get_closest_marker(name="block_network")
-    if marker is not None:
-        validate_block_network_mark(marker)
+def allowed_hosts(request: SubRequest) -> List[str]:
+    """List of regexes to match hosts to where connection must be allowed."""
+    block_network = request.node.get_closest_marker(name="block_network")
     config = request.getfixturevalue("vcr_config")
-    # If network blocking is enabled there is one exception - if VCR is in recording mode (any mode except "none")
     # Take `--allowed-hosts` with the most priority:
     #  - `block_network` mark
     #  - CLI option
-    #  - vcr_config fixture
-    default_block = marker or request.config.getoption("--block-network")
+    #  - `vcr_config` fixture
     allowed_hosts = (
-        getattr(marker, "kwargs", {}).get("allowed_hosts")
+        getattr(block_network, "kwargs", {}).get("allowed_hosts")
         or request.config.getoption("--allowed-hosts")
         or config.get("allowed_hosts")
     )
     if isinstance(allowed_hosts, str):
         allowed_hosts = allowed_hosts.split(",")
+    return allowed_hosts
+
+
+@pytest.fixture  # type: ignore
+def vcr_markers(request: SubRequest) -> List[Mark]:
+    """All markers applied to the certain test together with cassette names associated with each marker."""
+    return list(request.node.iter_markers(name="vcr"))
+
+
+@pytest.fixture(autouse=True)  # type: ignore
+def block_network(request: SubRequest, record_mode: str, vcr_markers: List[Mark]) -> Iterator[None]:
+    """Block network access in tests except for "none" VCR recording mode."""
+    block_network = request.node.get_closest_marker(name="block_network")
+    if block_network is not None:
+        validate_block_network_mark(block_network)
     if vcr_markers:
         # Take `record_mode` with the most priority:
         #  - Explicit CLI option
         #  - The `vcr_config` fixture
         #  - The `vcr` mark
+        config = request.getfixturevalue("vcr_config")
         merged_config = merge_kwargs(config, vcr_markers)
         # If `--record-mode` was not explicitly passed in CLI, then take one from the merged config
         if request.config.getoption("--record-mode") is None:
             record_mode = merged_config.get("record_mode", "none")
-    if default_block and (not request.getfixturevalue("vcr_markers") or record_mode == "none"):
+    # If network blocking is enabled there is one exception - if VCR is in recording mode (any mode except "none")
+    if (block_network or request.config.getoption("--block-network")) and (not vcr_markers or record_mode == "none"):
+        allowed_hosts = request.getfixturevalue("allowed_hosts")
         with network.blocking_context(allowed_hosts=allowed_hosts):
             yield
     else:

tests/test_plugin.py

@@ -66,3 +66,23 @@ def test_marker(default_cassette_name):
     result = testdir.runpytest()
     result.assert_outcomes(passed=1)
     assert result.ret == 0
+
+
+def test_lazy_vcr_config(testdir):
+    # When test does not involve VCR
+    testdir.makepyfile(
+        """
+        import pytest
+
+        @pytest.fixture
+        def vcr_config():
+            raise RuntimeError("Should not run")
+
+        def test_marker():
+            pass
+        """
+    )
+    # Then the `vcr_config` fixture should not be evaluated
+    result = testdir.runpytest()
+    result.assert_outcomes(passed=1)
+    assert result.ret == 0