chore: address PR feedback

Signed-off-by: Keith Zantow <kzantow@gmail.com>

spdx/v2/v2_2/json/empty_values_test.go

@@ -12,7 +12,7 @@ func Test_omitsAppropriateProperties(t *testing.T) {
 	tests := []struct {
 		name     string
 		pkg      spdx.Package
-		validate func(t *testing.T, got string)
+		validate func(t *testing.T, got map[string]interface{})
 	}{
 		{
 			name: "include packageVerificationCode exclusions",
@@ -21,7 +21,7 @@ func Test_omitsAppropriateProperties(t *testing.T) {
 					ExcludedFiles: []string{},
 				},
 			},
-			validate: func(t *testing.T, got string) {
+			validate: func(t *testing.T, got map[string]interface{}) {
 				require.Contains(t, got, "packageVerificationCode")
 			},
 		},
@@ -32,7 +32,7 @@ func Test_omitsAppropriateProperties(t *testing.T) {
 					Value: "1234",
 				},
 			},
-			validate: func(t *testing.T, got string) {
+			validate: func(t *testing.T, got map[string]interface{}) {
 				require.Contains(t, got, "packageVerificationCode")
 			},
 		},
@@ -41,7 +41,7 @@ func Test_omitsAppropriateProperties(t *testing.T) {
 			pkg: spdx.Package{
 				PackageVerificationCode: common.PackageVerificationCode{},
 			},
-			validate: func(t *testing.T, got string) {
+			validate: func(t *testing.T, got map[string]interface{}) {
 				require.NotContains(t, got, "packageVerificationCode")
 			},
 		},
@@ -51,7 +51,10 @@ func Test_omitsAppropriateProperties(t *testing.T) {
 		t.Run(test.name, func(t *testing.T) {
 			got, err := json.Marshal(test.pkg)
 			require.NoError(t, err)
-			test.validate(t, string(got))
+			var unmarshalled map[string]interface{}
+			err = json.Unmarshal(got, &unmarshalled)
+			require.NoError(t, err)
+			test.validate(t, unmarshalled)
 		})
 	}
 }

spdx/v2/v2_2/package.go

@@ -132,8 +132,10 @@ func (p Package) MarshalJSON() ([]byte, error) {
 		return nil, err
 	}
 
-	// remove empty packageVerificationCode entries -- required by 2.2 JSON schema but
-	// omitempty has no effect since it is a non-comparable struct and not a pointer
+	// remove empty packageVerificationCode entries -- required by SPDX 2.2 but
+	// omitempty has no effect since it is a non-comparable struct and not a pointer, so we
+	// manually check to determine if there is a valid value to output and omit the field if not
+	// see: https://spdx.github.io/spdx-spec/v2.2.2/package-information/#79-package-verification-code-field
 	if p.PackageVerificationCode.Value == "" && p.PackageVerificationCode.ExcludedFiles == nil {
 		var values map[string]interface{}
 		err = json.Unmarshal(data, &values)