Fix order-dependent test

Be careful to initialise counters before taking snapshot

CHANGELOG.md

@@ -6,6 +6,7 @@
   (`*`) by default.
 * Updated golangci-lint to v1.47.3 (developers should update to this version)
 * Delete merkle package, use [github.com/transparency-dev/merkle](https://pkg.go.dev/github.com/transparency-dev/merkle) instead.
+* #2792: Fixed order-dependent unit test.
 
 ## v1.4.2
 

log/operation_manager_test.go

@@ -166,14 +166,15 @@ func TestOperationManagerExecutePassError(t *testing.T) {
 	mockLogOp.EXPECT().ExecutePass(gomock.Any(), logID1, infoMatcher).Return(1, nil)
 	mockLogOp.EXPECT().ExecutePass(gomock.Any(), logID2, infoMatcher).Return(0, errors.New("test error"))
 
+	info := defaultOperationInfo(registry)
+	lom := NewOperationManager(info, mockLogOp) // initialises counters
+
 	// Do not run this test in parallel with any other that affects the signingRuns or failedSigningRuns counters.
 	log1SigningRuns := testonly.NewCounterSnapshot(signingRuns, logID1Label)
 	log1FailedSigningRuns := testonly.NewCounterSnapshot(failedSigningRuns, logID1Label)
 	log2SigningRuns := testonly.NewCounterSnapshot(signingRuns, logID2Label)
 	log2FailedSigningRuns := testonly.NewCounterSnapshot(failedSigningRuns, logID2Label)
 
-	info := defaultOperationInfo(registry)
-	lom := NewOperationManager(info, mockLogOp)
 	lom.OperationSingle(ctx)
 
 	// Check that logID1 has 1 successful signing run, 0 failed.
@@ -318,14 +319,15 @@ func TestOperationManagerOperationLoopExecutePassError(t *testing.T) {
 		}
 	}).Return(0, errors.New("test error"))
 
+	info := defaultOperationInfo(registry)
+	lom := NewOperationManager(info, mockLogOp) // initialises counters
+
 	// Do not run this test in parallel with any other that affects the signingRuns or failedSigningRuns counters.
 	log1SigningRuns := testonly.NewCounterSnapshot(signingRuns, logID1Label)
 	log1FailedSigningRuns := testonly.NewCounterSnapshot(failedSigningRuns, logID1Label)
 	log2SigningRuns := testonly.NewCounterSnapshot(signingRuns, logID2Label)
 	log2FailedSigningRuns := testonly.NewCounterSnapshot(failedSigningRuns, logID2Label)
 
-	info := defaultOperationInfo(registry)
-	lom := NewOperationManager(info, mockLogOp)
 	lom.OperationLoop(ctx)
 
 	// Check that logID1 has 1 successful signing run, 0 failed.

monitoring/testonly/delta.go

@@ -34,6 +34,9 @@ type CounterSnapshot struct {
 // by the given labels. This value can be compared to future values to determine
 // how it has changed over time.
 func NewCounterSnapshot(c monitoring.Counter, labels ...string) CounterSnapshot {
+	if c == nil {
+		panic("can't take snapshot of nil counter")
+	}
 	return CounterSnapshot{
 		c:      c,
 		labels: labels,