Issue 87: simple Providers.of(instance) method to facilitate your unit tests
git-svn-id: https://google-guice.googlecode.com/svn/trunk@332 d779f126-a31b-0410-b53b-1d3aecad763e
diff --git a/src/com/google/inject/util/Providers.java b/src/com/google/inject/util/Providers.java
new file mode 100644
index 0000000..92da1cb
--- /dev/null
+++ b/src/com/google/inject/util/Providers.java
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2007 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.inject.util;
+
+import com.google.inject.Provider;
+
+/**
+ * Static utility methods for creating and working with instances of
+ * {@link Provider}.
+ *
+ * @author Kevin Bourrillion (kevinb9n@gmail.com)
+ */
+public final class Providers {
+
+ private Providers() {}
+
+ /**
+ * Returns a provider which always provides {@code instance}. This should not
+ * be necessary to use in your application, but is helpful for several types
+ * of unit tests.
+ *
+ * @param instance the instance that should always be provided. This is also
+ * permitted to be null, to enable aggressive testing, although in real
+ * life a Guice-supplied Provider will never return null.
+ */
+ public static <T> Provider<T> of(final T instance) {
+ return new Provider<T>() {
+ public T get() {
+ return instance;
+ }
+ };
+ }
+}
diff --git a/test/com/google/inject/AllTests.java b/test/com/google/inject/AllTests.java
index 300a168..4d8715b 100644
--- a/test/com/google/inject/AllTests.java
+++ b/test/com/google/inject/AllTests.java
@@ -21,6 +21,7 @@
import com.google.inject.internal.ReferenceMapTest;
import com.google.inject.internal.ReferenceMapTestSuite;
import com.google.inject.matcher.MatcherTest;
+import com.google.inject.util.ProvidersTest;
import junit.framework.Test;
import junit.framework.TestSuite;
@@ -63,6 +64,8 @@
suite.addTestSuite(IntegrationTest.class);
+ suite.addTestSuite(ProvidersTest.class);
+
return suite;
}
}
diff --git a/test/com/google/inject/util/ProvidersTest.java b/test/com/google/inject/util/ProvidersTest.java
new file mode 100644
index 0000000..b99d126
--- /dev/null
+++ b/test/com/google/inject/util/ProvidersTest.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2007 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.inject.util;
+
+import com.google.inject.Provider;
+import junit.framework.TestCase;
+
+/**
+ * Unit tests for {@link Providers}.
+ *
+ * @author Kevin Bourrillion (kevinb9n@gmail.com)
+ */
+public class ProvidersTest extends TestCase {
+
+ public void testOfInstance() {
+ String foo = "foo";
+ Provider<String> p = Providers.of(foo);
+ assertSame(foo, p.get());
+ assertSame(foo, p.get());
+ }
+
+ public void testOfNull() {
+ Provider<String> p = Providers.of(null);
+ assertNull(p.get());
+ }
+}
