[java] InvalidLogMessageFormat: Add test case for #253

pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/errorprone/xml/InvalidLogMessageFormat.xml

@@ -1181,6 +1181,33 @@ public class Foo {
 		LOGGER.warn("Exception {}", IllegalStateException.class.getName(), exception());
 	}
 }
+]]></code>
+    </test-code>
+
+    <test-code>
+        <description>slf4j: [java] InvalidLogMessageFormat doesn't handle formats assembled via multi-stage concatenation #253</description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class Slf4JMessageFormatConcatenation {
+    private static final Logger LOG = LoggerFactory.getLogger(Slf4JMessageFormatConcatenation.class);
+
+    public void run() {
+        String message = "Field: {}";
+        // some code
+        String error = message + ", error: {}";
+
+        LOG.error(error, "fieldValue", "errorMessage"); // two placeholders, two args
+
+        // string concat with 7 params
+        int a, b, c, d, e, f, g;
+        LOGGER.warn("blah blah a={}, b={}, c={}, " +
+                            "d={}, e={}, f={}, g={}",
+                    a, b, c, d, e, f, g);
+    }
+}
 ]]></code>
     </test-code>
 </test-data>