[498324] Fix failing Dot xtext editor content assistant test cases.

- Use the "org.eclipse.xtext.common.Terminals" within the DotShape.xtext
sub-grammar to ensure that the proposal provider of the dot node shape
attribute works properly.
- Activate corresponding Dot Content Assistant test cases.
- Modify the DotValidator and DotAttributes test cases to accept the
newly generated validation failure messages.

org.eclipse.gef.dot.tests/src/org/eclipse/gef/dot/tests/DotAttributesTests.java

@@ -1365,7 +1365,7 @@ public void node_shape() {
 			fail("Expecting IllegalArgumentException.");
 		} catch (IllegalArgumentException e) {
 			assertEquals(
-					"Cannot set node attribute 'shape' to 'foo'. The value 'foo' is not a syntactically correct shape: Mismatched character 'o' expecting 'l'.",
+					"Cannot set node attribute 'shape' to 'foo'. The value 'foo' is not a syntactically correct shape: No viable alternative at input 'foo'.",
 					e.getMessage());
 		}
 	}

org.eclipse.gef.dot.tests/src/org/eclipse/gef/dot/tests/DotContentAssistTests.java

@@ -654,20 +654,18 @@ public void node_shape() throws Exception {
 				.expectContent("graph {1[ shape=\"Mrecord\" ]}");
 
 		// test local attribute values with prefix
-		// TODO: activate
-		// newBuilder().append("graph {1[ shape=pr ]}")
-		// .assertTextAtCursorPosition(18, "primersite", "promoter",
-		// "proteasesite", "proteinstab", ",", ";", "]")
-		// .applyProposal(18, "primersite")
-		// .expectContent("graph {1[ shape=primersite ]}");
+		newBuilder().append("graph {1[ shape=pr ]}")
+				.assertTextAtCursorPosition(18, "primersite", "promoter",
+						"proteasesite", "proteinstab", ",", ";", "]")
+				.applyProposal(18, "primersite")
+				.expectContent("graph {1[ shape=primersite ]}");
 
 		// test local attribute values with quotes and prefix
-		// TODO: activate
-		// newBuilder().append("graph {1[ shape=\"pro\" ]}")
-		// .assertTextAtCursorPosition(20, "promoter", "proteasesite",
-		// "proteinstab")
-		// .applyProposal(20, "proteinstab")
-		// .expectContent("graph {1[ shape=\"proteinstab\" ]}");
+		newBuilder().append("graph {1[ shape=\"pro\" ]}")
+				.assertTextAtCursorPosition(20, "promoter", "proteasesite",
+						"proteinstab")
+				.applyProposal(20, "proteinstab")
+				.expectContent("graph {1[ shape=\"proteinstab\" ]}");
 	}
 
 	@Test

org.eclipse.gef.dot.tests/src/org/eclipse/gef/dot/tests/DotValidatorTests.java

@@ -242,7 +242,7 @@ public void testWrongNodeShape() throws Exception {
 
 		validationTestHelper.assertError(dotAst,
 				DotPackage.eINSTANCE.getAttribute(), DotAttributes.SHAPE__N,
-				"The value 'foo' is not a syntactically correct shape: Mismatched character 'o' expecting 'l'.");
+				"The value 'foo' is not a syntactically correct shape: No viable alternative at input 'foo'.");
 
 		// verify that this is the only reported issue
 		Assert.assertEquals(1, validationTestHelper.validate(dotAst).size());

org.eclipse.gef.dot/src/org/eclipse/gef/dot/internal/parser/DotShape.xtext

@@ -10,10 +10,9 @@
  *     Tamas Miklossy (itemis AG) - initial API and implementation (bug #441352)
  *     
  *******************************************************************************/
-grammar org.eclipse.gef.dot.internal.parser.DotShape
+grammar org.eclipse.gef.dot.internal.parser.DotShape with org.eclipse.xtext.common.Terminals
 
 generate shape "http://www.eclipse.org/gef/dot/internal/parser/DotShape"
-import "http://www.eclipse.org/emf/2002/Ecore" as ecore
 
 Shape: 
 	shape = (PolygonBasedShape | RecordBasedShape);