Adding utils/fixture_mapper

utils/fixture_mapper/fixture_mapper.py

@@ -0,0 +1,85 @@
+"""Graph project test fixture usage.
+
+This script will map the fixtures used by pytest and generate a graph of which fixtures
+are used by which tests. It runs pytest twice to generate a list of the fixtures and
+then the test setup plan. Together these can be used to get the fixture graph without
+running the tests themselves.
+
+Note that networkx is not currently a project or developer requirement for the project.
+"""
+
+import io
+import subprocess
+
+import networkx
+
+# Read in the output of `pytest --fixtures > pytest_fixtures.log`
+print("Running: pytest ../../tests --fixtures")
+fixtures_output = subprocess.run(
+    "pytest ../../tests --fixtures".split(" "), capture_output=True, text=True
+)
+fixture_lines = io.StringIO(fixtures_output.stdout).readlines()
+
+# Reduce to the lines containing fixtures declared in the tests/ files and convert to a
+# dictionary of fixture name and location
+fixtures = [
+    line.strip().split(" -- ") for line in fixture_lines if "-- ../../tests/" in line
+]
+fixtures_dict = {ky: vl for (ky, vl) in fixtures}
+
+# Dump universal fixtures
+fixtures_dict.pop("reset_module_registry")
+
+# Read in the output of `pytest ../../tests --setup-plan`
+print("Running: pytest ../../tests --setup-plan")
+setup_output = subprocess.run(
+    "pytest ../../tests --setup-plan".split(" "), capture_output=True, text=True
+)
+setup_lines = io.StringIO(setup_output.stdout).readlines()
+
+tests: dict[str, dict] = {}
+current_fixtures: dict[str, str] = {}
+current_test = ""
+
+for line in setup_lines:
+    if line.startswith("../../tests/"):
+        # save the fixture list associated with the previous test, checking that
+        # previous parameterisations are using the same fixtures
+        if current_test in tests:
+            assert current_fixtures == tests[current_test]
+        tests[current_test] = current_fixtures.copy()
+        current_fixtures.clear()
+
+        # Get the test name discarding any parameterisation label
+        current_test = line.strip().split("[")[0]
+    else:
+        data = line.strip().split()
+        if len(data) > 0 and data[0] == "SETUP" and data[2] in fixtures_dict:
+            current_fixtures[data[2]] = fixtures_dict[data[2]]
+
+# Write to text
+with open("tests_fixtures.txt", "w") as outfile:
+    for test_name, test_fixtures in tests.items():
+        outfile.write(test_name + "\n")
+        outfile.writelines([" * " + v + "\n" for v in test_fixtures])
+
+print("Fixture report generated")
+
+# Convert to graph
+graph = networkx.Graph()
+
+for test_name, test_fixtures in tests.items():
+    graph.add_node(test_name, label=test_name, color="#0000FF")
+
+    for fix_name, fix_loc in test_fixtures.items():
+        graph.add_node(fix_name, label=fix_name, loc=fix_loc, color="#FF0000")
+        graph.add_edge(test_name, fix_name)
+
+networkx.write_graphml(graph, "tests_fixtures.graphml")
+
+print(
+    f"Fixture graph generated:\n"
+    f"Tests found: {len(tests)}\n"
+    f"Fixtures found: {len(fixtures)}\n"
+    f"Number of fixture usages: {sum([len(v) for v in tests.values()])}\n"
+)