tests/frontend/rebuild.py: Add test_modify_and_revert

This tests that, in non-strict mode, a cached artifact matching the
strict cache key is preferred to a more recent artifact matching only
the weak cache key.

1 files changed, 41 insertions, 0 deletions

diff --git a/tests/frontend/rebuild.py b/tests/frontend/rebuild.py
index a4851e09a..d54eedfb9 100644
--- a/tests/frontend/rebuild.py
+++ b/tests/frontend/rebuild.py
@@ -41,3 +41,44 @@ def test_rebuild(datafiles, cli, strict):
         assert "target.bst" in built_elements
     else:
         assert "target.bst" not in built_elements
+
+
+# Test that a cached artifact matching the strict cache key is preferred
+# to a more recent artifact matching only the weak cache key.
+@pytest.mark.datafiles(DATA_DIR)
+@pytest.mark.parametrize("strict", ["strict", "non-strict"])
+def test_modify_and_revert(datafiles, cli, strict):
+    project = str(datafiles)
+
+    # First build target and dependencies
+    result = cli.run(project=project, args=["build", "target.bst"])
+    result.assert_success()
+
+    # Remember cache key of first build
+    target_cache_key = cli.get_element_key(project, "target.bst")
+
+    # Modify dependency
+    new_header_path = os.path.join(project, "files", "dev-files", "usr", "include", "new.h")
+    with open(new_header_path, "w") as f:
+        f.write("#define NEW")
+
+    # Trigger rebuild. This will also rebuild the unmodified target as this
+    # follows a strict build plan.
+    result = cli.run(project=project, args=["build", "target.bst"])
+    result.assert_success()
+
+    assert "target.bst" in result.get_built_elements()
+    assert cli.get_element_key(project, "target.bst") != target_cache_key
+
+    # Revert previous modification in dependency
+    os.unlink(new_header_path)
+
+    # Rebuild again, everything should be cached.
+    result = cli.run(project=project, args=["build", "target.bst"])
+    result.assert_success()
+    assert len(result.get_built_elements()) == 0
+
+    # Verify that cache key now again matches the first build in both
+    # strict and non-strict mode.
+    cli.configure({"projects": {"test": {"strict": strict == "strict"}}})
+    assert cli.get_element_key(project, "target.bst") == target_cache_key