Fix runStep condition for mavenExecuteStaticCodeChecks (#2009)

This change fixes the step mavenExecuteStaticCodeChecks to skip execution
if no tool is configured. Previously, the step was executed even when both 
supported tools, i.e., PMD and SpotBugs were disabled.

cmd/mavenExecuteStaticCodeChecks.go

@@ -23,7 +23,8 @@ func runMavenStaticCodeChecks(config *mavenExecuteStaticCodeChecksOptions, telem
 	var goals []string
 
 	if !config.SpotBugs && !config.Pmd {
-		log.Entry().Fatal("Neither SpotBugs nor Pmd are configured. At least one of those tools have to be enabled")
+		log.Entry().Warnf("Neither SpotBugs nor Pmd are configured. Skipping step execution")
+		return nil
 	}
 
 	if testModulesExcludes := maven.GetTestModulesExcludes(); testModulesExcludes != nil {

cmd/mavenExecuteStaticCodeChecks_test.go

@@ -4,8 +4,6 @@ import (
 	"os"
 	"testing"
 
-	"github.com/SAP/jenkins-library/pkg/log"
-
 	"github.com/SAP/jenkins-library/pkg/mock"
 
 	"github.com/SAP/jenkins-library/pkg/maven"
@@ -51,16 +49,15 @@ func TestRunMavenStaticCodeChecks(t *testing.T) {
 		assert.Nil(t, err)
 		assert.Equal(t, expected, execMockRunner.Calls[0])
 	})
-	t.Run("should log fatal if all tools are turned off", func(t *testing.T) {
-		var hasFailed bool
-		log.Entry().Logger.ExitFunc = func(int) { hasFailed = true }
+	t.Run("should warn and skip execution if all tools are turned off", func(t *testing.T) {
 		execMockRunner := mock.ExecMockRunner{}
 		config := mavenExecuteStaticCodeChecksOptions{
 			SpotBugs: false,
 			Pmd:      false,
 		}
-		_ = runMavenStaticCodeChecks(&config, nil, &execMockRunner)
-		assert.True(t, hasFailed, "expected command to exit with fatal")
+		err := runMavenStaticCodeChecks(&config, nil, &execMockRunner)
+		assert.Nil(t, err)
+		assert.Nil(t, execMockRunner.Calls)
 	})
 }