fix

com.avaloq.tools.ddk.xtext.test.core/src/com/avaloq/tools/ddk/xtext/test/validation/AbstractValidationTest.java

@@ -786,9 +786,7 @@ protected void assertDiagnostic(final String issueCode) {
    *          the code of the issue to look for
    */
   protected void assertDiagnostic(final EObject model, final String issueCode) {
-    if (model == null) {
-      fail("Issue with code '" + issueCode + "' cannot be found because the model is null");
-    }
+    assertNotNull("Issue with code '" + issueCode + "' cannot be found because the model is null", model);
     assertDiagnostic(getXtextTestUtil().getDiagnostician().validate(model), issueCode);
   }
 
@@ -811,10 +809,7 @@ protected void assertNoDiagnostic(final String issueCode) {
    *          the code of the issue to look for
    */
   protected void assertNoDiagnostic(final EObject model, final String issueCode) {
-    if (model == null) {
-      fail("Issue with code '" + issueCode + "' cannot be found because the model is null");
-    }
-
+    assertNotNull("Issue with code '" + issueCode + "' cannot be found because the model is null", model);
     assertNoDiagnostic(getXtextTestUtil().getDiagnostician().validate(model), issueCode);
   }
 
@@ -832,7 +827,7 @@ protected void assertNoDiagnostics() {
    *          the model in which to look for issues, may be {@code null}
    */
   protected void assertNoDiagnostics(final EObject model) {
-    assertNotNull("Assertion cannot be checked because the model is null", model == null);
+    assertNotNull("Assertion cannot be checked because the model is null", model);
     assertNoDiagnostics(getXtextTestUtil().getDiagnostician().validate(model));
   }
 
@@ -855,10 +850,7 @@ protected void assertDiagnosticMessage(final String message) {
    *          the message of the issue to look for
    */
   protected void assertDiagnosticMessage(final EObject model, final String message) {
-    if (model == null) {
-      fail("Message '" + message + "' cannot be found because the model is null");
-    }
-
+    assertNotNull("Message '" + message + "' cannot be found because the model is null", model);
     assertDiagnosticMessage(getXtextTestUtil().getDiagnostician().validate(model), message);
   }