mantle/kola: limit testbank when doing a rerun

Today we see an issue when trying to do a rerun when a tag was provided
because of the filtertests function logic where all the tests matching
the tag get rerun, not just the tests that failed. Let's limit the
testsBank when doing the rerun so only failed tests can possibly get
selected/run.

Fixes coreos#3041

mantle/kola/harness.go

@@ -855,23 +855,23 @@ func runProvidedTests(testsBank map[string]*register.Test, patterns []string, mu
 
 	detectedFailedWarnTrueTests := len(getWarnTrueFailedTests(testResults.getResults())) != 0
 
-	testsToRerun := getRerunnable(testResults.getResults())
-	failedTests := testsToRerun
+	testsToRerun := getRerunnable(testsBank, testResults.getResults())
+	numFailedTests := len(testsToRerun)
 	if len(testsToRerun) > 0 && rerun {
 		newOutputDir := filepath.Join(outputDir, "rerun")
 		fmt.Printf("\n\n======== Re-running failed tests (flake detection) ========\n\n")
-		reRunErr := runProvidedTests(testsBank, testsToRerun, multiply, false, rerunSuccessTags, pltfrm, newOutputDir)
-		if reRunErr == nil && allTestsAllowRerunSuccess(testsBank, testsToRerun, rerunSuccessTags) {
-			runErr = nil             // reset to success since all tests allowed rerun success
-			failedTests = []string{} // zero out the list of failed tests
+		reRunErr := runProvidedTests(testsToRerun, []string{"*"}, multiply, false, rerunSuccessTags, pltfrm, newOutputDir)
+		if reRunErr == nil && allTestsAllowRerunSuccess(testsToRerun, rerunSuccessTags) {
+			runErr = nil       // reset to success since all tests allowed rerun success
+			numFailedTests = 0 // zero out the tally of failed tests
 		} else {
 			runErr = reRunErr
 		}
 
 	}
 
 	// Return ErrWarnOnTestFail when ONLY tests with warn:true feature failed
-	if detectedFailedWarnTrueTests && len(failedTests) == 0 {
+	if detectedFailedWarnTrueTests && numFailedTests == 0 {
 		return ErrWarnOnTestFail
 	} else {
 		return runErr
@@ -895,7 +895,7 @@ func getWarnTrueFailedTests(tests []*harness.H) []string {
 	return warnTrueFailedTests
 }
 
-func allTestsAllowRerunSuccess(testsBank map[string]*register.Test, testsToRerun, rerunSuccessTags []string) bool {
+func allTestsAllowRerunSuccess(testsToRerun map[string]*register.Test, rerunSuccessTags []string) bool {
 	// Always consider the special AllowRerunSuccessTag that is added
 	// by the test harness in some failure scenarios.
 	rerunSuccessTags = append(rerunSuccessTags, AllowRerunSuccessTag)
@@ -913,7 +913,7 @@ func allTestsAllowRerunSuccess(testsBank map[string]*register.Test, testsToRerun
 	// allow rerun success then just exit early.
 	for _, test := range testsToRerun {
 		testAllowsRerunSuccess := false
-		for _, tag := range testsBank[test].Tags {
+		for _, tag := range test.Tags {
 			if rerunSuccessTagMap[tag] {
 				testAllowsRerunSuccess = true
 			}
@@ -973,20 +973,30 @@ func IsWarningOnFailure(testName string) bool {
 	return false
 }
 
-func getRerunnable(tests []*harness.H) []string {
-	var testsToRerun []string
-	for _, h := range tests {
+func getRerunnable(testsBank map[string]*register.Test, testResults []*harness.H) map[string]*register.Test {
+	// First get the names of the tests that need to rerun
+	var testNamesToRerun []string
+	for _, h := range testResults {
 		// The current nonexclusive test wrapper would have all non-exclusive tests.
 		// We would add all those tests for rerunning if none of the non-exclusive
 		// subtests start due to some initial failure.
 		if nonexclusiveWrapperMatch.MatchString(h.Name()) && !h.GetNonExclusiveTestStarted() {
 			if h.Failed() {
-				testsToRerun = append(testsToRerun, h.Subtests()...)
+				testNamesToRerun = append(testNamesToRerun, h.Subtests()...)
 			}
 		} else {
 			name, isRerunnable := GetRerunnableTestName(h.Name())
 			if h.Failed() && isRerunnable {
-				testsToRerun = append(testsToRerun, name)
+				testNamesToRerun = append(testNamesToRerun, name)
+			}
+		}
+	}
+	// Then convert the list of names into a list of a register.Test objects
+	testsToRerun := make(map[string]*register.Test)
+	for name, t := range testsBank {
+		for _, rerun := range testNamesToRerun {
+			if name == rerun {
+				testsToRerun[name] = t
 			}
 		}
 	}