added tests for StringLiteralEquality

src/testinputs/com/puppycrawl/tools/checkstyle/coding/InputStringLiteralEquality.java

@@ -0,0 +1,47 @@
+package com.puppycrawl.tools.checkstyle.
+
+/**
+ * Input file for the StringLiteralEqualityCheck
+ * @author Lars Kühne
+ */
+public class InputStringLiteralEquality
+{
+    void foo(String name)
+    {
+        if (name == "Lars")
+        {
+            // flagged, should use equals
+        }
+
+        if ("Oleg" == name)
+        {
+            // flagged, should use equals
+        }
+
+        if ("Oliver" == "Oliver")
+        {
+            // doesn't make much sense because this can be evaluated
+            // to true at compile time, but is flagged anyway
+        }
+
+        String compare = "Rick";
+        if (name == compare)
+        {
+            // currently not flagged.
+            //
+            // Implementing this is very complicated, we would need
+            // - type info on the == operands
+            // - prevent false alarms where the user explicitly wants
+            //   to compare object identities
+            //
+            // My current feeling is that we should leave finding
+            // this one to manual code inspections. After all MCI is
+            // what some of us get paid for :-)
+        }
+
+        if ("Rick".toUpperCase() == "Rick".toLowerCase())
+        {
+            // completly dynamic, don't flag
+        }
+    }
+}