Fail early if file which should be uploaded does not exist. (#909)

Right now we fail with some error message from curl.

test/groovy/TmsUploadTest.groovy

@@ -1,5 +1,8 @@
 import com.sap.piper.JenkinsUtils
 import com.sap.piper.integration.TransportManagementService
+
+import hudson.AbortException
+
 import org.junit.After
 import org.junit.Before
 import org.junit.Rule
@@ -19,6 +22,7 @@ public class TmsUploadTest extends BasePiperTest {
     private JenkinsStepRule stepRule = new JenkinsStepRule(this)
     private JenkinsLoggingRule loggingRule = new JenkinsLoggingRule(this)
     private JenkinsEnvironmentRule envRule = new JenkinsEnvironmentRule(this)
+    private JenkinsFileExistsRule fileExistsRules = new JenkinsFileExistsRule(this, ['dummy.mtar'])
 
     def tmsStub
     def jenkinsUtilsStub
@@ -56,6 +60,7 @@ public class TmsUploadTest extends BasePiperTest {
         .around(stepRule)
         .around(loggingRule)
         .around(envRule)
+        .around(fileExistsRules)
         .around(new JenkinsCredentialsRule(this)
             .withCredentials('TMS_ServiceKey', serviceKeyContent))
 
@@ -161,6 +166,27 @@ public class TmsUploadTest extends BasePiperTest {
         assertThat(loggingRule.log, containsString("[TransportManagementService] Corresponding Transport Request: 'My custom description for testing.' (Id: '2000')"))
     }
 
+    @Test
+    public void failOnMissingMtaFile() {
+
+        thrown.expect(AbortException)
+        thrown.expectMessage('Mta file \'dummy.mtar\' does not exist.')
+
+        fileExistsRules.existingFiles.remove('dummy.mtar')
+        jenkinsUtilsStub = new JenkinsUtilsMock("Test User")
+
+        stepRule.step.tmsUpload(
+            script: nullScript,
+            juStabUtils: utils,
+            jenkinsUtilsStub: jenkinsUtilsStub,
+            transportManagementService: tmsStub,
+            mtaPath: 'dummy.mtar',
+            nodeName: 'myNode',
+            credentialsId: 'TMS_ServiceKey',
+            customDescription: 'My custom description for testing.'
+        )
+    }
+
     def mockTransportManagementService() {
         return new TransportManagementService(nullScript, [:]) {
             def authentication(String uaaUrl, String oauthClientId, String oauthClientSecret) {

vars/tmsUpload.groovy

@@ -94,6 +94,10 @@ void call(Map parameters = [:]) {
         def nodeName = config.nodeName
         def mtaPath = config.mtaPath
 
+        if(!fileExists(mtaPath)) {
+            error("Mta file '${mtaPath}' does not exist.")
+        }
+
         if (config.verbose) {
             echo "[TransportManagementService] CredentialsId: '${config.credentialsId}'"
             echo "[TransportManagementService] Node name: '${nodeName}'"