pkg/bisect: improve config minimization tests

Change a test to actually produce a new config as it is supposed
to do during config minimization and check the resulting config.

Add a regression test for the bug where we committed a broken config.

2 files changed, 20 insertions, 5 deletions

diff --git a/pkg/bisect/bisect_test.go b/pkg/bisect/bisect_test.go
index 32d11af13..6815c1ab8 100644
--- a/pkg/bisect/bisect_test.go
+++ b/pkg/bisect/bisect_test.go
@@ -39,7 +39,7 @@ func (env *testEnv) BuildKernel(compilerBin, userspaceDir, cmdlineFile, sysctlFi
 		kernelSign = "same-sign"
 	}
 	env.config = string(kernelConfig)
-	if env.config == "baseline-fails" {
+	if env.config == "baseline-fails" || env.config == "broken-build" {
 		return "", kernelSign, fmt.Errorf("Failure")
 	}
 	return "", kernelSign, nil
@@ -51,7 +51,7 @@ func (env *testEnv) Test(numVMs int, reproSyz, reproOpts, reproC []byte) ([]erro
 		env.config == "baseline-skip" {
 		return nil, fmt.Errorf("broken build")
 	}
-	if (env.config == "baseline-repro" || env.config == "original config") &&
+	if (env.config == "baseline-repro" || env.config == "new-minimized-config" || env.config == "original config") &&
 		(!env.test.fix && commit >= env.test.culprit || env.test.fix &&
 			commit < env.test.culprit) {
 		return crashErrors(numVMs, "crash occurs"), nil
@@ -183,6 +183,15 @@ var bisectionTests = []BisectionTest{
 		resultingConfig: "baseline-repro",
 	},
 	{
+		name:            "cause-finds-cause-baseline-broken-build",
+		startCommit:     905,
+		commitLen:       1,
+		expectRep:       true,
+		culprit:         602,
+		baselineConfig:  "baseline-broken-build",
+		resultingConfig: "original config",
+	},
+	{
 		name:            "cause-finds-cause-baseline-does-not-repro",
 		startCommit:     905,
 		commitLen:       1,
@@ -216,7 +225,7 @@ var bisectionTests = []BisectionTest{
 		expectRep:       true,
 		culprit:         602,
 		baselineConfig:  "minimize-succeeds",
-		resultingConfig: "original config",
+		resultingConfig: "new-minimized-config",
 	},
 	{
 		name:           "cause-finds-cause-minimize-fails",
diff --git a/pkg/vcs/testos.go b/pkg/vcs/testos.go
index c8746a684..ea369f529 100644
--- a/pkg/vcs/testos.go
+++ b/pkg/vcs/testos.go
@@ -30,8 +30,14 @@ func (ctx *testos) EnvForCommit(binDir, commit string, kernelConfig []byte) (*Bi
 
 func (ctx *testos) Minimize(original, baseline []byte, trace io.Writer,
 	pred func(test []byte) (BisectResult, error)) ([]byte, error) {
-	if string(baseline) == "minimize-fails" {
+	switch string(baseline) {
+	case "minimize-fails":
 		return nil, fmt.Errorf("minimization failure")
+	case "minimize-succeeds":
+		return []byte("new-minimized-config"), nil
+	case "baseline-broken-build":
+		return []byte("broken-build"), nil
+	default:
+		return original, nil
 	}
-	return original, nil
 }