From 55a6b0b26b7385ba594986758a6865c642675ada Mon Sep 17 00:00:00 2001
From: Mincong HUANG <mincong.h@gmail.com>
Date: Wed, 11 Nov 2020 13:58:27 +0100
Subject: [PATCH 1/2] Add feature flag

---
 .../reliability/featureflag/MyJob.java        | 21 +++++++
 .../reliability/featureflag/MyJobTest.java    | 56 +++++++++++++++++++
 2 files changed, 77 insertions(+)
 create mode 100644 reliability/src/test/java/io/mincong/reliability/featureflag/MyJob.java
 create mode 100644 reliability/src/test/java/io/mincong/reliability/featureflag/MyJobTest.java

diff --git a/reliability/src/test/java/io/mincong/reliability/featureflag/MyJob.java b/reliability/src/test/java/io/mincong/reliability/featureflag/MyJob.java
new file mode 100644
index 00000000..ac48d42f
--- /dev/null
+++ b/reliability/src/test/java/io/mincong/reliability/featureflag/MyJob.java
@@ -0,0 +1,21 @@
+package io.mincong.reliability.featureflag;
+
+import java.util.Set;
+
+public class MyJob {
+
+  private final Set<String> values;
+
+  public MyJob(Set<String> values) {
+    this.values = values;
+  }
+
+  public void run() {
+    var isNewFeatureEnabled = Boolean.getBoolean("NEW_FEATURE_ENABLED");
+    if (isNewFeatureEnabled) {
+      values.add("new");
+    } else {
+      values.add("old");
+    }
+  }
+}
diff --git a/reliability/src/test/java/io/mincong/reliability/featureflag/MyJobTest.java b/reliability/src/test/java/io/mincong/reliability/featureflag/MyJobTest.java
new file mode 100644
index 00000000..535d7bef
--- /dev/null
+++ b/reliability/src/test/java/io/mincong/reliability/featureflag/MyJobTest.java
@@ -0,0 +1,56 @@
+package io.mincong.reliability.featureflag;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.HashSet;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+
+class MyJobTest {
+
+  @AfterEach
+  void tearDown() {
+    System.clearProperty("NEW_FEATURE_ENABLED");
+  }
+
+  @Test
+  void itShouldEnableNewFeature() {
+    // Given
+    System.setProperty("NEW_FEATURE_ENABLED", "True");
+    var set = new HashSet<String>();
+    var job = new MyJob(set);
+
+    // When
+    job.run();
+
+    // Then
+    assertThat(set).containsExactly("new");
+  }
+
+  @Test
+  void itShouldDisableNewFeature() {
+    // Given
+    System.setProperty("NEW_FEATURE_ENABLED", "False");
+    var set = new HashSet<String>();
+    var job = new MyJob(set);
+
+    // When
+    job.run();
+
+    // Then
+    assertThat(set).containsExactly("old");
+  }
+
+  @Test
+  void itShouldFallback() {
+    // Given
+    var set = new HashSet<String>();
+    var job = new MyJob(set);
+
+    // When
+    job.run();
+
+    // Then
+    assertThat(set).containsExactly("old");
+  }
+}

From 0a50fcffc64aebf1bb370cbfa40928080e7fd549 Mon Sep 17 00:00:00 2001
From: Mincong HUANG <mincong.h@gmail.com>
Date: Sun, 15 Nov 2020 17:42:43 +0100
Subject: [PATCH 2/2] Add URL

---
 .../test/java/io/mincong/reliability/featureflag/MyJob.java   | 4 ++++
 .../java/io/mincong/reliability/featureflag/MyJobTest.java    | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/reliability/src/test/java/io/mincong/reliability/featureflag/MyJob.java b/reliability/src/test/java/io/mincong/reliability/featureflag/MyJob.java
index ac48d42f..074459eb 100644
--- a/reliability/src/test/java/io/mincong/reliability/featureflag/MyJob.java
+++ b/reliability/src/test/java/io/mincong/reliability/featureflag/MyJob.java
@@ -2,6 +2,10 @@
 
 import java.util.Set;
 
+/**
+ * @author Mincong Huang
+ * @blog https://mincong.io/2020/11/11/feature-flag/
+ */
 public class MyJob {
 
   private final Set<String> values;
diff --git a/reliability/src/test/java/io/mincong/reliability/featureflag/MyJobTest.java b/reliability/src/test/java/io/mincong/reliability/featureflag/MyJobTest.java
index 535d7bef..d520b414 100644
--- a/reliability/src/test/java/io/mincong/reliability/featureflag/MyJobTest.java
+++ b/reliability/src/test/java/io/mincong/reliability/featureflag/MyJobTest.java
@@ -6,6 +6,10 @@
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 
+/**
+ * @author Mincong Huang
+ * @blog https://mincong.io/2020/11/11/feature-flag/
+ */
 class MyJobTest {
 
   @AfterEach