From c225ff983a7198d3999343fd0c4254914efa40e6 Mon Sep 17 00:00:00 2001
From: Stefan Birkner <mail@stefan-birkner.de>
Date: Fri, 9 Oct 2020 00:53:57 +0200
Subject: [PATCH] Replace System Rules with System Lambda

System Lambda is more specific. It only wraps the part of the code that
reads the environment variables. In addition System Lambda is
independent from the test framework and no obstacle for moving to
another test framework (e.g. JUnit Lambda).
---
 pom.xml                                           |  4 ++--
 .../tokens/AbstractAccessTokenRefresherTest.java  | 13 +++++--------
 .../stups/tokens/AccessTokenBuilderTest.java      | 15 ++++++---------
 3 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/pom.xml b/pom.xml
index f6b38fd..ee51189 100644
--- a/pom.xml
+++ b/pom.xml
@@ -134,8 +134,8 @@
         </dependency>
         <dependency>
             <groupId>com.github.stefanbirkner</groupId>
-            <artifactId>system-rules</artifactId>
-            <version>1.19.0</version>
+            <artifactId>system-lambda</artifactId>
+            <version>1.1.0</version>
             <scope>test</scope>
         </dependency>
     </dependencies>
diff --git a/src/test/java/org/zalando/stups/tokens/AbstractAccessTokenRefresherTest.java b/src/test/java/org/zalando/stups/tokens/AbstractAccessTokenRefresherTest.java
index c6ace0d..0b55b49 100644
--- a/src/test/java/org/zalando/stups/tokens/AbstractAccessTokenRefresherTest.java
+++ b/src/test/java/org/zalando/stups/tokens/AbstractAccessTokenRefresherTest.java
@@ -15,13 +15,13 @@
  */
 package org.zalando.stups.tokens;
 
+import static com.github.stefanbirkner.systemlambda.SystemLambda.withEnvironmentVariable;
+
 import java.util.Arrays;
 import java.util.List;
 
 import org.assertj.core.api.Assertions;
-import org.junit.Rule;
 import org.junit.Test;
-import org.junit.contrib.java.lang.system.EnvironmentVariables;
 import org.mockito.Mockito;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -31,9 +31,6 @@ public class AbstractAccessTokenRefresherTest {
     private static final String FIXED_TOKENS = "one=DSAFDASASDFDA,two=DSFADFADFADFADFA,three=ADAFDAFADFAFEWRDFADFASDF";
     private static final String EXPECTED_MESSAGE = "No token available for tokenId 'four'. Tokens are available for the following tokenIds [one, two, three]";
 
-    @Rule
-    public final EnvironmentVariables environmentVariables = new EnvironmentVariables();
-
     @Test
     public void testListToString() {
         List<String> keys = Arrays.asList("One", "Two", "Three");
@@ -41,11 +38,11 @@ public void testListToString() {
     }
 
     @Test
-    public void testExceptionMessage() {
-        environmentVariables.set("OAUTH2_ACCESS_TOKENS", FIXED_TOKENS);
+    public void testExceptionMessage() throws Exception {
         TokenRefresherConfiguration configuration = Mockito.mock(TokenRefresherConfiguration.class);
         AbstractAccessTokenRefresher refresher = new TestTokenRefresher(configuration);
-        refresher.initializeFixedTokensFromEnvironment();
+        withEnvironmentVariable("OAUTH2_ACCESS_TOKENS", FIXED_TOKENS)
+                .execute(refresher::initializeFixedTokensFromEnvironment);
         String availableTokenIds = refresher.getAvailableTokenIds();
         Assertions.assertThat(availableTokenIds).isEqualTo("[one, two, three]");
         try {
diff --git a/src/test/java/org/zalando/stups/tokens/AccessTokenBuilderTest.java b/src/test/java/org/zalando/stups/tokens/AccessTokenBuilderTest.java
index 42b574c..ba446db 100644
--- a/src/test/java/org/zalando/stups/tokens/AccessTokenBuilderTest.java
+++ b/src/test/java/org/zalando/stups/tokens/AccessTokenBuilderTest.java
@@ -15,6 +15,7 @@
  */
 package org.zalando.stups.tokens;
 
+import static com.github.stefanbirkner.systemlambda.SystemLambda.withEnvironmentVariable;
 import static org.assertj.core.api.Assertions.assertThat;
 
 import java.io.File;
@@ -27,7 +28,6 @@
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
-import org.junit.contrib.java.lang.system.EnvironmentVariables;
 import org.junit.rules.TemporaryFolder;
 import org.mockito.Mockito;
 import org.mockito.internal.util.io.IOUtil;
@@ -49,9 +49,6 @@ public class AccessTokenBuilderTest {
     @Rule
     public TemporaryFolder tempFolder = new TemporaryFolder();
 
-    @Rule
-    public final EnvironmentVariables environmentVariables = new EnvironmentVariables();
-
 	@Before
 	public void createCredentials() throws IOException {
 		File tempDir = tempFolder.newFolder();
@@ -150,9 +147,9 @@ public void noEnvironmentSet() {
 
     @Test
     public void notAnUri_OAUTH2_ACCESS_TOKEN_URL() {
-        environmentVariables.set("OAUTH2_ACCESS_TOKEN_URL", "::::");
         try {
-            Tokens.createAccessTokens();
+			withEnvironmentVariable("OAUTH2_ACCESS_TOKEN_URL", "::::")
+					.execute(Tokens::createAccessTokens);
             Assertions.fail("Not expected to reach this point");
         } catch (Exception e) {
             assertThat(e.getMessage())
@@ -161,9 +158,9 @@ public void notAnUri_OAUTH2_ACCESS_TOKEN_URL() {
     }
 
     @Test
-    public void usinEnvCreatesBuilder() {
-        environmentVariables.set("OAUTH2_ACCESS_TOKEN_URL", "https://somwhere.test/tokens");
-        AccessTokensBuilder builder = Tokens.createAccessTokens();
+    public void usinEnvCreatesBuilder() throws Exception {
+        AccessTokensBuilder builder = withEnvironmentVariable("OAUTH2_ACCESS_TOKEN_URL", "https://somwhere.test/tokens")
+						.execute(Tokens::createAccessTokens);
         Assertions.assertThat(builder).isNotNull();
     }
 }