Update filter-junit.go parsing code to combine test cases from multiple test directories

Author: pwschuurman

test/k8s-integration/filter-junit.go

@@ -72,13 +72,15 @@ func (s SkipReason) MarshalText() ([]byte, error) {
 // MergeJUnit merges all junit xml files found in sourceDirectories into a single xml file at destination, using the filter.
 // The merging removes duplicate skipped tests. The original files are deleted.
 func MergeJUnit(testFilter string, sourceDirectories []string, destination string) error {
-	var junit TestSuite
 	var data []byte
 
 	re := regexp.MustCompile(testFilter)
 
 	var mergeErrors []string
 	var filesToDelete []string
+
+	// Keep only matching testcases. Testcases skipped in all test runs are only stored once.
+	filtered := map[string]TestCase{}
 	for _, dir := range sourceDirectories {
 		files, err := os.ReadDir(dir)
 		if err != nil {
@@ -96,24 +98,26 @@ func MergeJUnit(testFilter string, sourceDirectories []string, destination strin
 			if err != nil {
 				return err
 			}
-			if err = xml.Unmarshal(data, &junit); err != nil {
-				return err
+			var testSuiteData TestSuite
+			if err = xml.Unmarshal(data, &testSuiteData); err != nil {
+				return fmt.Errorf("failed to unmarshal XML file %v: %w", fullFilename, err)
+			}
+
+			for _, testcase := range testSuiteData.TestCases {
+				if !re.MatchString(testcase.Name) {
+					continue
+				}
+				entry, ok := filtered[testcase.Name]
+				if !ok || // not present yet
+					entry.Skipped != "" && testcase.Skipped == "" { // replaced skipped test with real test run
+					filtered[testcase.Name] = testcase
+				}
 			}
 		}
 	}
 
 	// Keep only matching testcases. Testcases skipped in all test runs are only stored once.
-	filtered := map[string]TestCase{}
-	for _, testcase := range junit.TestCases {
-		if !re.MatchString(testcase.Name) {
-			continue
-		}
-		entry, ok := filtered[testcase.Name]
-		if !ok || // not present yet
-			entry.Skipped != "" && testcase.Skipped == "" { // replaced skipped test with real test run
-			filtered[testcase.Name] = testcase
-		}
-	}
+	var junit TestSuite
 	junit.TestCases = nil
 	for _, testcase := range filtered {
 		junit.TestCases = append(junit.TestCases, testcase)
@@ -122,7 +126,7 @@ func MergeJUnit(testFilter string, sourceDirectories []string, destination strin
 	// Re-encode.
 	data, err := xml.MarshalIndent(junit, "", "  ")
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to marshal junit data: %w", err)
 	}
 
 	if err = os.WriteFile(destination, data, 0644); err != nil {