Function TestDownloadCacheWorkdirMismatch

internal/policy/source/source_test.go:605–635

Test for https://issues.redhat.com/browse/EC-936, where we had multiple symbolic links pointing to the same policy download within the same workdir causing Rego compile issue

(t *testing.T)

// symbolic links pointing to the same policy download within the same workdir
// causing Rego compile issue
func TestDownloadCacheWorkdirMismatch(t *testing.T) {
	t.Cleanup(func() {
		downloadCache = sync.Map{}
	})
	tmp := t.TempDir()

	source := &mockPolicySource{&mock.Mock{}}
	source.On("PolicyUrl").Return("policy-url")
	source.On("Subdir").Return("subdir")

	// same URL downloaded to workdir1
	precachedDest := uniqueDestination(tmp, "subdir", source.PolicyUrl())
	require.NoError(t, os.MkdirAll(precachedDest, 0o755))
	downloadCache.Store("policy-url", func() (string, cacheContent) {
		return precachedDest, cacheContent{}
	})

	// when working in workdir2
	workdir2 := filepath.Join(tmp, "workdir2")

	// first invocation symlinks back to workdir1
	destination1, _, err := getPolicyThroughCache(context.Background(), source, workdir2, func(s1, s2 string) (metadata.Metadata, error) { return nil, nil })
	require.NoError(t, err)

	// second invocation should not create a second symlink and duplicate the
	// source files within workdir2
	destination2, _, err := getPolicyThroughCache(context.Background(), source, workdir2, func(s1, s2 string) (metadata.Metadata, error) { return nil, nil })
	require.NoError(t, err)

	assert.Equal(t, destination1, destination2)
}

// TestConcurrentPolicyCachingRaceCondition reproduces the "file exists" error
// that occurs when multiple workers simultaneously try to create symlinks from