Added Results[x].ID = x invariant assertions to every TestingBatch test.

testing.go

@@ -224,3 +224,13 @@ func AssertThreadCount(t *testing.T, pool *SpyThreadPool, want int) {
 		t.Errorf("got %d threads used, want %d", got, want)
 	}
 }
+
+// AssertResultIDInvariant checks that each key in TestingBatch.Results
+// equals to the its value`s ID field.
+func AssertResultIDInvariant(t *testing.T, b *TestingBatch) {
+    for k, v := range b.Results {
+        if k != v.ID {
+            t.Errorf("invariant violation: %d != Results[%d].ID (which is %d)", k, k, v.ID)
+        }
+    }
+}

testing_batch_test.go

@@ -132,6 +132,7 @@ func TestTestingBatch(t *testing.T) {
 			2: cptest.OK,
 		}
 
+		cptest.AssertResultIDInvariant(t, batch)
 		cptest.AssertVerdicts(t, batch.Results, want)
 		cptest.AssertCallCount(t, "proc.Run()", proc.CallCount(), 2)
 		cptest.AssertThreadCount(t, pool, 2)
@@ -166,6 +167,7 @@ func TestTestingBatch(t *testing.T) {
 			2: cptest.OK,
 		}
 
+		cptest.AssertResultIDInvariant(t, batch)
 		cptest.AssertVerdicts(t, batch.Results, want)
 		cptest.AssertCallCount(t, "proc.Run()", proc.CallCount(), 2)
 		cptest.AssertThreadCount(t, pool, 2)
@@ -211,6 +213,7 @@ func TestTestingBatch(t *testing.T) {
 			2: cptest.WA,
 		}
 
+		cptest.AssertResultIDInvariant(t, batch)
 		cptest.AssertVerdicts(t, batch.Results, want)
 		cptest.AssertCallCount(t, "proc.Run()", proc.CallCount(), 2)
 		cptest.AssertThreadCount(t, pool, 2)
@@ -246,6 +249,7 @@ func TestTestingBatch(t *testing.T) {
 				2: cptest.WA,
 			}
 
+			cptest.AssertResultIDInvariant(t, batch)
 			cptest.AssertVerdicts(t, batch.Results, want)
 			cptest.AssertCallCount(t, "proc.Run()", proc.CallCount(), 2)
 			cptest.AssertThreadCount(t, pool, 2)
@@ -318,6 +322,7 @@ func TestTestingBatch(t *testing.T) {
 				5: cptest.IE,
 			}
 
+			cptest.AssertResultIDInvariant(t, batch)
 			cptest.AssertVerdicts(t, batch.Results, want)
 			cptest.AssertCallCount(t, "proc.Run()", proc.CallCount(), 5)
 			cptest.AssertThreadCount(t, pool, 3)
@@ -381,6 +386,7 @@ func TestTestingBatch(t *testing.T) {
 				1: 3 * time.Second,
 			}
 
+			cptest.AssertResultIDInvariant(t, batch)
 			cptest.AssertVerdicts(t, batch.Results, testsWant)
 			cptest.AssertThreadCount(t, pool, 1)
 
@@ -453,6 +459,7 @@ func TestTestingBatch(t *testing.T) {
 				1: 3 * time.Second,
 			}
 
+			cptest.AssertResultIDInvariant(t, batch)
 			cptest.AssertVerdicts(t, batch.Results, testsWant)
 			cptest.AssertThreadCount(t, pool, 1)
 
@@ -529,6 +536,7 @@ func TestTestingBatch(t *testing.T) {
 				2: 3 * time.Second,
 			}
 
+			cptest.AssertResultIDInvariant(t, batch)
 			cptest.AssertVerdicts(t, batch.Results, testsWant)
 			cptest.AssertThreadCount(t, pool, 1)
 
@@ -606,6 +614,7 @@ func TestTestingBatch(t *testing.T) {
 				2: 3 * time.Second,
 			}
 
+			cptest.AssertResultIDInvariant(t, batch)
 			cptest.AssertVerdicts(t, batch.Results, testsWant)
 			cptest.AssertThreadCount(t, pool, 2)
 
@@ -722,6 +731,7 @@ func TestTestingBatch(t *testing.T) {
 				4: 3 * time.Second,
 			}
 
+			cptest.AssertResultIDInvariant(t, batch)
 			cptest.AssertVerdicts(t, batch.Results, testsWant)
 			cptest.AssertThreadCount(t, pool, 2)