diff --git a/src/main/java/com/launchdarkly/client/TestFeatureStore.java b/src/main/java/com/launchdarkly/client/TestFeatureStore.java
new file mode 100644
index 000000000..b8107ce21
--- /dev/null
+++ b/src/main/java/com/launchdarkly/client/TestFeatureStore.java
@@ -0,0 +1,40 @@
+package com.launchdarkly.client;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * A decorated {@link InMemoryFeatureStore} which provides functionality to create (or override) "on" or "off" feature flags for all users.
+ *
+ * Using this store is useful for testing purposes when you want to have runtime support for turning specific features "on" or "off".
+ *
+ */
+public class TestFeatureStore extends InMemoryFeatureStore {
+
+    private AtomicInteger version = new AtomicInteger(0);
+
+    /**
+     * Turns a feature, identified by key, "on" for every user. If the feature rules already exist in the store then it will override it to be "on" for every {@link LDUser}.
+     * If the feature rule is not currently in the store, it will create one that is "on" for every {@link LDUser}.
+     *
+     * @param key the key of the feature flag to be "on".
+     */
+    public void turnFeatureOn(String key) {
+        writeFeatureRep(key, new Variation.Builder<>(true, 100).build());
+    }
+
+    /**
+     * Turns a feature, identified by key, "off" for every user. If the feature rules already exists in the store then it will override it to be "off" for every {@link LDUser}.
+     * If the feature rule is not currently in the store, it will create one that is "off" for every {@link LDUser}.
+     *
+     * @param key the key of the feature flag to be "off".
+     */
+    public void turnFeatureOff(String key) {
+        writeFeatureRep(key, new Variation.Builder<>(false, 100).build());
+    }
+
+    private void writeFeatureRep(final String key, final Variation<Boolean> variation) {
+        FeatureRep<Boolean> newFeature = new FeatureRep.Builder<Boolean>(String.format("test-%s", key), key)
+                .variation(variation).version(version.incrementAndGet()).build();
+        upsert(key, newFeature);
+    }
+}
diff --git a/src/test/java/com/launchdarkly/client/LDClientTest.java b/src/test/java/com/launchdarkly/client/LDClientTest.java
index 78e020d4a..d0543c9ac 100644
--- a/src/test/java/com/launchdarkly/client/LDClientTest.java
+++ b/src/test/java/com/launchdarkly/client/LDClientTest.java
@@ -5,6 +5,8 @@
 import org.junit.Test;
 
 import java.io.IOException;
+import java.io.ObjectInput;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
@@ -12,6 +14,7 @@
 import static org.easymock.EasyMock.anyObject;
 import static org.easymock.EasyMock.expect;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 public class LDClientTest extends EasyMockSupport {
@@ -45,6 +48,76 @@ public void testOffline() throws IOException {
     verifyAll();
   }
 
+  @Test
+  public void testTestFeatureStoreFlagOn() throws IOException, InterruptedException, ExecutionException, TimeoutException {
+    TestFeatureStore testFeatureStore = new TestFeatureStore();
+    LDConfig config = new LDConfig.Builder()
+            .startWaitMillis(10L)
+            .stream(false)
+            .featureStore(testFeatureStore)
+            .build();
+
+    expect(initFuture.get(10L, TimeUnit.MILLISECONDS)).andReturn(new Object());
+    expect(pollingProcessor.start()).andReturn(initFuture);
+    expect(pollingProcessor.initialized()).andReturn(true).times(1);
+    expect(eventProcessor.sendEvent(anyObject(Event.class))).andReturn(true);
+    replayAll();
+
+    client = createMockClient(config);
+    testFeatureStore.turnFeatureOn("key");
+    assertTrue("Test flag should be on, but was not.", client.toggle("key", new LDUser("user"), false));
+
+    verifyAll();
+  }
+
+  @Test
+  public void testTestFeatureStoreFlagOff() throws IOException, InterruptedException, ExecutionException, TimeoutException {
+    TestFeatureStore testFeatureStore = new TestFeatureStore();
+    LDConfig config = new LDConfig.Builder()
+            .startWaitMillis(10L)
+            .stream(false)
+            .featureStore(testFeatureStore)
+            .build();
+
+    expect(initFuture.get(10L, TimeUnit.MILLISECONDS)).andReturn(new Object());
+    expect(pollingProcessor.start()).andReturn(initFuture);
+    expect(pollingProcessor.initialized()).andReturn(true).times(1);
+    expect(eventProcessor.sendEvent(anyObject(Event.class))).andReturn(true);
+    replayAll();
+
+    client = createMockClient(config);
+    testFeatureStore.turnFeatureOff("key");
+    assertFalse("Test flag should be off, but was on (the default).", client.toggle("key", new LDUser("user"), true));
+
+    verifyAll();
+  }
+
+  @Test
+  public void testTestFeatureStoreFlagOnThenOff() throws IOException, InterruptedException, ExecutionException, TimeoutException {
+    TestFeatureStore testFeatureStore = new TestFeatureStore();
+    LDConfig config = new LDConfig.Builder()
+            .startWaitMillis(10L)
+            .stream(false)
+            .featureStore(testFeatureStore)
+            .build();
+
+    expect(initFuture.get(10L, TimeUnit.MILLISECONDS)).andReturn(new Object());
+    expect(pollingProcessor.start()).andReturn(initFuture);
+    expect(pollingProcessor.initialized()).andReturn(true).times(2);
+    expect(eventProcessor.sendEvent(anyObject(Event.class))).andReturn(true).times(2);
+    replayAll();
+
+    client = createMockClient(config);
+
+    testFeatureStore.turnFeatureOn("key");
+    assertTrue("Test flag should be on, but was not.", client.toggle("key", new LDUser("user"), false));
+
+    testFeatureStore.turnFeatureOff("key");
+    assertFalse("Test flag should be off, but was on (the default).", client.toggle("key", new LDUser("user"), true));
+
+    verifyAll();
+  }
+
   @Test
   public void testUseLdd() throws IOException {
     LDConfig config = new LDConfig.Builder()