Introduce MockEnvironment in the spring-test module

For legacy reasons, a MockEnvironment implementation already exists in multiple places within Spring's test suite; however, it is not available to the general public.

This commit promotes MockEnvironment to a first-class citizen in the spring-test module, alongside the existing MockPropertySource.

In addition, the following house cleaning has been performed.

 - deleted MockPropertySource from the spring-expression module
 - deleted MockEnvironment from the "spring" integration testing module
 - updated test copies of MockPropertySource and MockEnvironment
 - documented MockEnvironment and MockPropertySource in the testing
   chapter of the reference manual

Issue: SPR-9492

spring-test/src/main/java/org/springframework/mock/env/MockEnvironment.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2002-2012 the original author or authors.
+ *
+ * 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 org.springframework.mock.env;
+
+import org.springframework.core.env.AbstractEnvironment;
+import org.springframework.core.env.ConfigurableEnvironment;
+
+/**
+ * Simple {@link ConfigurableEnvironment} implementation exposing
+ * {@link #setProperty(String, String)} and {@link #withProperty(String, String)}
+ * methods for testing purposes.
+ * 
+ * @author Chris Beams
+ * @author Sam Brannen
+ * @since 3.2
+ * @see org.springframework.mock.env.MockPropertySource
+ */
+public class MockEnvironment extends AbstractEnvironment {
+
+	private MockPropertySource propertySource = new MockPropertySource();
+
+	/**
+	 * Create a new {@code MockEnvironment} with a single {@link MockPropertySource}.
+	 */
+	public MockEnvironment() {
+		getPropertySources().addLast(propertySource);
+	}
+
+	/**
+	 * Set a property on the underlying {@link MockPropertySource} for this environment.
+	 */
+	public void setProperty(String key, String value) {
+		propertySource.setProperty(key, value);
+	}
+
+	/**
+	 * Convenient synonym for {@link #setProperty} that returns the current instance.
+	 * Useful for method chaining and fluent-style use.
+	 * @return this {@link MockEnvironment} instance
+	 * @see MockPropertySource#withProperty(String, String)
+	 */
+	public MockEnvironment withProperty(String key, String value) {
+		this.setProperty(key, value);
+		return this;
+	}
+
+}

spring-test/src/main/java/org/springframework/mock/env/MockPropertySource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2012 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -36,7 +36,7 @@ import org.springframework.core.env.PropertySource;
  *
  * @author Chris Beams
  * @since 3.1
- * @see MockEnvironment
+ * @see org.springframework.mock.env.MockEnvironment
  */
 public class MockPropertySource extends PropertiesPropertySource {
 
@@ -75,8 +75,8 @@ public class MockPropertySource extends PropertiesPropertySource {
 	}
 
 	/**
-	 * Create a new {@code MockPropertySource} with with the given name and backed by the given
-	 * {@link Properties} object
+	 * Create a new {@code MockPropertySource} with the given name and backed by the given
+	 * {@link Properties} object.
 	 * @param name the {@linkplain #getName() name} of the property source
 	 * @param properties the properties to use
 	 */
@@ -100,4 +100,5 @@ public class MockPropertySource extends PropertiesPropertySource {
 		this.setProperty(name, value);
 		return this;
 	}
+
 }

spring-test/src/main/java/org/springframework/mock/env/package-info.java

@@ -0,0 +1,10 @@
+/**
+ * This package contains mock implementations of the
+ * {@link org.springframework.core.env.Environment Environment} and
+ * {@link org.springframework.core.env.PropertySource PropertySource}
+ * abstractions introduced in Spring 3.1.
+ * 
+ * <p>These <em>mocks</em> are useful for developing <em>out-of-container</em>
+ * unit tests for code that depends on environment-specific properties.
+ */
+package org.springframework.mock.env;