ConfigTest: Add test for parsing invalid group header

Test that an exception is raised for an invalid group header:

  [group "foo" ]
     foo = bar

i.e. where there is a space between the group subsection name
and the closing ']'.

Change-Id: I8933ae100b77634b0afb66bb8aa43d24c955799e
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ConfigTest.java

@@ -1450,6 +1450,13 @@ public class ConfigTest {
 		assertEquals("xt", parseEscapedSubsection("\"x\\t\""));
 	}
 
+	@Test
+	public void testInvalidGroupHeader() throws ConfigInvalidException {
+		expectedEx.expect(ConfigInvalidException.class);
+		expectedEx.expectMessage(JGitText.get().badGroupHeader);
+		parse("[foo \"bar\" ]\nfoo=bar\n");
+	}
+
 	private static void assertValueRoundTrip(String value)
 			throws ConfigInvalidException {
 		assertValueRoundTrip(value, value);