Adding Intent API tests
diff --git a/core/api/src/test/java/org/onlab/onos/net/intent/ImmutableClassChecker.java b/core/api/src/test/java/org/onlab/onos/net/intent/ImmutableClassChecker.java
new file mode 100644
index 0000000..0e63af9
--- /dev/null
+++ b/core/api/src/test/java/org/onlab/onos/net/intent/ImmutableClassChecker.java
@@ -0,0 +1,125 @@
+package org.onlab.onos.net.intent;
+//TODO is this the right package?
+
+import org.hamcrest.Description;
+import org.hamcrest.StringDescription;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+
+/**
+ * Hamcrest style class for verifying that a class follows the
+ * accepted rules for immutable classes.
+ *
+ * The rules that are enforced for immutable classes:
+ *    - the class must be declared final
+ *    - all data members of the class must be declared private and final
+ *    - the class must not define any setter methods
+ */
+
+public class ImmutableClassChecker {
+
+    private String failureReason = "";
+
+    /**
+     * Method to determine if a given class is a properly specified
+     * immutable class.
+     *
+     * @param clazz the class to check
+     * @return true if the given class is a properly specified immutable class.
+     */
+    private boolean isImmutableClass(Class<?> clazz) {
+        // class must be declared final
+        if (!Modifier.isFinal(clazz.getModifiers())) {
+            failureReason = "a class that is not final";
+            return false;
+        }
+
+        // class must have only final and private data members
+        for (final Field field : clazz.getDeclaredFields()) {
+            if (field.getName().startsWith("__cobertura")) {
+                //  cobertura sticks these fields into classes - ignore them
+                continue;
+            }
+            if (!Modifier.isFinal(field.getModifiers())) {
+                failureReason = "a field named '" + field.getName() +
+                                "' that is not final";
+                return false;
+            }
+            if (!Modifier.isPrivate(field.getModifiers())) {
+                //
+                // NOTE: We relax the recommended rules for defining immutable
+                // objects and allow "static final" fields that are not
+                // private. The "final" check was already done above so we
+                // don't repeat it here.
+                //
+                if (!Modifier.isStatic(field.getModifiers())) {
+                    failureReason = "a field named '" + field.getName() +
+                                "' that is not private and is not static";
+                    return false;
+                }
+            }
+        }
+
+        //  class must not define any setters
+        for (final Method method : clazz.getMethods()) {
+            if (method.getDeclaringClass().equals(clazz)) {
+                if (method.getName().startsWith("set")) {
+                    failureReason = "a class with a setter named '" + method.getName() + "'";
+                    return false;
+                }
+            }
+        }
+
+        return true;
+    }
+
+    /**
+     * Describe why an error was reported.  Uses Hamcrest style Description
+     * interfaces.
+     *
+     * @param description the Description object to use for reporting the
+     *                    mismatch
+     */
+    public void describeMismatch(Description description) {
+        description.appendText(failureReason);
+    }
+
+    /**
+     * Describe the source object that caused an error, using a Hamcrest
+     * Matcher style interface.  In this case, it always returns
+     * that we are looking for a properly defined utility class.
+     *
+     * @param description the Description object to use to report the "to"
+     *                    object
+     */
+    public void describeTo(Description description) {
+        description.appendText("a properly defined immutable class");
+    }
+
+    /**
+     * Assert that the given class adheres to the utility class rules.
+     *
+     * @param clazz the class to check
+     *
+     * @throws java.lang.AssertionError if the class is not a valid
+     *         utility class
+     */
+    public static void assertThatClassIsImmutable(Class<?> clazz) {
+        final ImmutableClassChecker checker = new ImmutableClassChecker();
+        if (!checker.isImmutableClass(clazz)) {
+            final Description toDescription = new StringDescription();
+            final Description mismatchDescription = new StringDescription();
+
+            checker.describeTo(toDescription);
+            checker.describeMismatch(mismatchDescription);
+            final String reason =
+                    "\n" +
+                    "Expected: is \"" + toDescription.toString() + "\"\n" +
+                    "    but : was \"" + mismatchDescription.toString() + "\"";
+
+            throw new AssertionError(reason);
+        }
+    }
+}