Add test for check mode conflicts in check configurations

In addition to being pointless, having the same check mode in multiple companion configuration fields results in the
configuration behavior being dependent on which order the fields are processed in, which may change.

Author: per1234

check/checkconfigurations/checkconfigurations_test.go

@@ -26,7 +26,7 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestConfigurations(t *testing.T) {
+func TestConfigurationResolution(t *testing.T) {
 	for _, checkConfiguration := range checkconfigurations.Configurations() {
 		for checkMode := range checkmode.Types {
 			enabled, err := check.IsEnabled(checkConfiguration, map[checkmode.Type]bool{checkMode: true})
@@ -38,3 +38,30 @@ func TestConfigurations(t *testing.T) {
 		}
 	}
 }
+
+func TestConfigurationCheckModeConflict(t *testing.T) {
+	// Having the same check mode in multiple configurations results in the configuration behavior being dependent on which order the fields are processed in, which may change.
+	for _, checkConfiguration := range checkconfigurations.Configurations() {
+		conflict, checkMode := checkModeConflict(checkConfiguration.DisableModes, checkConfiguration.EnableModes)
+		assert.False(t, conflict, fmt.Sprintf("Duplicated check mode %s in enable configuration of check %s", checkMode, checkConfiguration.ID))
+
+		conflict, checkMode = checkModeConflict(checkConfiguration.InfoModes, checkConfiguration.WarningModes, checkConfiguration.ErrorModes)
+		assert.False(t, conflict, fmt.Sprintf("Duplicated check mode %s in level configuration of check %s", checkMode, checkConfiguration.ID))
+	}
+}
+
+// checkModeConflict checks whether the same check mode is present in multiple configuration fields.
+func checkModeConflict(configurations ...[]checkmode.Type) (bool, checkmode.Type) {
+	modeCounter := 0
+	checkModeMap := make(map[checkmode.Type]bool)
+	for _, configuration := range configurations {
+		for _, checkMode := range configuration {
+			modeCounter += 1
+			checkModeMap[checkMode] = true
+			if len(checkModeMap) < modeCounter {
+				return true, checkMode
+			}
+		}
+	}
+	return false, checkmode.Default
+}