Improve comment

Tests could easily be marked "skip" because the user doesn't want to run them in their environment, and in this common case the set of tests will be non-nil

check/test.go

@@ -145,7 +145,7 @@ func (ts *tests) execute(s string) *testOutput {
 	finalOutput := &testOutput{}
 
 	// If no tests are defined return with empty finalOutput.
-	// This is usually the case for checks of type: "skip".
+	// This may be the case for checks of type: "skip".
 	if ts == nil {
 		return finalOutput
 	}