Set up unit test that tracks orphan-oss/ognl#125 - this test failing …

…is a sign that this bug may have been fixed. The bug causes OGNL to incorrectly identify a case of 2 varargs method that also has a no-args option as problematic in a particular condition (see the github issue for more detail).

§Currently the only side-effect of this bug is to print an error message to application stderr in this case, e.g.
```
Two vararg methods with same score(0): "public javax.ws.rs.client.Invocation$Builder org.jboss.resteasy.client.jaxrs.internal.ClientWebTarget.request(javax.ws.rs.core.MediaType[])" and "public javax.ws.rs.client.Invocation$Builder org.jboss.resteasy.client.jaxrs.internal.ClientWebTarget.request(java.lang.String[])" please report!
```

guice/common/src/test/java/com/peterphi/std/guice/common/ognl/OgnlIssue125Test.java

@@ -0,0 +1,104 @@
+package com.peterphi.std.guice.common.ognl;
+
+import ognl.AbstractMemberAccess;
+import ognl.Node;
+import ognl.Ognl;
+import ognl.OgnlContext;
+import org.junit.ComparisonFailure;
+import org.junit.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.lang.reflect.Member;
+import java.lang.reflect.Modifier;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Unit test set up to track <a href="https://github.com/jkuhnert/ognl/issues/125">https://github.com/jkuhnert/ognl/issues/125</a>.<br
+ * /> This unit test will pass <strong>until this bug is fixed</strong>
+ */
+public class OgnlIssue125Test
+{
+	public interface TestInterface
+	{
+		String request();
+
+		String request(String... args);
+
+		String request(int... args);
+	}
+
+	public static class TestInterfaceImpl implements TestInterface
+	{
+		@Override
+		public String request()
+		{
+			return "noargs";
+		}
+
+
+		@Override
+		public String request(final String... args)
+		{
+			return "varargs string";
+		}
+
+
+		@Override
+		public String request(final int... args)
+		{
+			return "varargs int";
+		}
+	}
+
+	public static class OgnlRoot
+	{
+		public TestInterfaceImpl get()
+		{
+			return new TestInterfaceImpl();
+		}
+	}
+
+	private static class OGNLPublicMemberAccess extends AbstractMemberAccess
+	{
+		@Override
+		public boolean isAccessible(final Map context, final Object target, final Member member, final String propertyName)
+		{
+			return Modifier.isPublic(member.getModifiers());
+		}
+	}
+
+
+	/**
+	 * @throws Exception         on setup failure
+	 * @throws ComparisonFailure if the bug is still present; if this test starts faiing it is a sign that the bug may be fixed -
+	 *                           remove the expected=ComparisonFailure!
+	 */
+	@Test(expected = ComparisonFailure.class)
+	public void testOgnl() throws Exception
+	{
+		final PrintStream stderr = System.err;
+		try
+		{
+			final OgnlRoot obj = new OgnlRoot();
+			final Node ognl = (Node) Ognl.parseExpression("get().request()");
+
+			final ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+			System.setErr(new PrintStream(buffer));
+			{
+				assertEquals("noargs", ognl.getValue(new OgnlContext(null, null, new OGNLPublicMemberAccess()), obj));
+			}
+			System.err.flush();
+
+			// This fails currently due to OGNL issue #125
+			assertEquals("Expecting no stderr output from OGNL call", "", buffer.toString("UTF-8"));
+		}
+		finally
+		{
+			// Restore stderr
+			System.setErr(stderr);
+		}
+	}
+}