Bug 1943284: Fix nil function in buildContext return values

staging/operator-registry/pkg/lib/indexer/indexer.go

@@ -396,6 +396,9 @@ func copyDatabaseTo(databaseFile, targetDir string) (string, error) {
 }
 
 func buildContext(generate bool, requestedDockerfile string) (buildDir, outDockerfile string, cleanup func(), err error) {
+	// set cleanup to a no-op until explicitly set
+	cleanup = func() {}
+
 	if generate {
 		buildDir = "./"
 		if len(requestedDockerfile) == 0 {

staging/operator-registry/pkg/lib/indexer/indexer_test.go

@@ -83,3 +83,61 @@ func TestGeneratePackageYaml(t *testing.T) {
 
 	_ = os.RemoveAll("./package.yaml")
 }
+
+func TestBuildContext(t *testing.T) {
+	// TODO(): Test does not currently have a clean way
+	// of testing the generated returned values such as
+	// outDockerfile and buildDir.
+
+	defaultBuildDirOnGenerate := "./"
+	fooDockerfile := "foo.Dockerfile"
+	defaultDockerfile := defaultDockerfileName
+
+	cases := []struct {
+		generate              bool
+		requestedDockerfile   string
+		expectedBuildDir      *string // return values not checked if nil
+		expectedOutDockerfile *string // return values not checked if nil
+	}{
+		{
+			generate:              true,
+			requestedDockerfile:   "",
+			expectedOutDockerfile: &defaultDockerfile,
+			expectedBuildDir:      &defaultBuildDirOnGenerate,
+		},
+		{
+			generate:              false,
+			requestedDockerfile:   "foo.Dockerfile",
+			expectedOutDockerfile: &fooDockerfile,
+			expectedBuildDir:      nil,
+		},
+		{
+			generate:              false,
+			requestedDockerfile:   "",
+			expectedOutDockerfile: nil,
+			expectedBuildDir:      nil,
+		},
+	}
+
+	for _, testCase := range cases {
+		actualBuildDir, actualOutDockerfile, actualCleanup, _ := buildContext(
+			testCase.generate, testCase.requestedDockerfile)
+
+		if actualCleanup == nil {
+			// prevent regression - cleanup should never be nil
+			t.Fatal("buildContext returned nil cleanup function")
+		}
+
+		if testCase.expectedOutDockerfile != nil && actualOutDockerfile != *testCase.expectedOutDockerfile {
+			t.Fatalf("comparing outDockerfile: expected %v actual %v",
+				*testCase.expectedOutDockerfile,
+				actualOutDockerfile)
+		}
+
+		if testCase.expectedBuildDir != nil && actualBuildDir != *testCase.expectedBuildDir {
+			t.Fatalf("comparing buildDir: expected %v actual %v",
+				*testCase.expectedBuildDir,
+				actualBuildDir)
+		}
+	}
+}