From 7626d5ccb355c4da74d9ca999e6b4278bd6adb05 Mon Sep 17 00:00:00 2001
From: Moritz Halbritter <moritz.halbritter@broadcom.com>
Date: Tue, 13 May 2025 15:38:25 +0200
Subject: [PATCH] Exercise 8

---
 components/library-autoconfigure/pom.xml      |   5 +
 .../config/GreetingAutoConfigurationTest.java | 101 ++++++++++++++++++
 2 files changed, 106 insertions(+)
 create mode 100644 components/library-autoconfigure/src/test/java/com/workshop/magic/config/GreetingAutoConfigurationTest.java

diff --git a/components/library-autoconfigure/pom.xml b/components/library-autoconfigure/pom.xml
index 3b632e9..571a3f0 100644
--- a/components/library-autoconfigure/pom.xml
+++ b/components/library-autoconfigure/pom.xml
@@ -33,5 +33,10 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-autoconfigure</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 </project>
diff --git a/components/library-autoconfigure/src/test/java/com/workshop/magic/config/GreetingAutoConfigurationTest.java b/components/library-autoconfigure/src/test/java/com/workshop/magic/config/GreetingAutoConfigurationTest.java
new file mode 100644
index 0000000..3e3522d
--- /dev/null
+++ b/components/library-autoconfigure/src/test/java/com/workshop/magic/config/GreetingAutoConfigurationTest.java
@@ -0,0 +1,101 @@
+package com.workshop.magic.config;
+
+import com.workshop.magic.service.GreetingService;
+import com.workshop.magic.service.slf4j.BeepGreetingService;
+import com.workshop.magic.service.slf4j.LoggerGreetingService;
+import com.workshop.magic.service.stdout.StdOutGreetingService;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.test.context.FilteredClassLoader;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class GreetingAutoConfigurationTest {
+    private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+            .withConfiguration(AutoConfigurations.of(GreetingAutoConfiguration.class));
+
+    @Test
+    void shouldProvideStdOutGreetingServiceByDefault() {
+        this.contextRunner.run(context -> {
+            assertThat(context).hasSingleBean(StdOutGreetingService.class);
+        });
+    }
+
+    @Test
+    void shouldProvideStdOutGreetingServiceWhenPropertyIsSet() {
+        this.contextRunner
+                .withPropertyValues("workshop.greeting.type=stdout")
+                .run(context -> {
+                    assertThat(context).hasSingleBean(StdOutGreetingService.class);
+                });
+    }
+
+    @Test
+    void shouldProvideLoggerGreetingServiceWhenPropertyIsSet() {
+        this.contextRunner
+                .withPropertyValues("workshop.greeting.type=logger")
+                .run(context -> {
+                    assertThat(context).hasSingleBean(LoggerGreetingService.class);
+                });
+    }
+
+    @Test
+    void shouldBackOffIfGreetingServiceIsDefinedByUser() {
+        this.contextRunner
+                .withBean(GreetingService.class, UserGreetingService::new)
+                .run(context -> {
+                    assertThat(context).hasSingleBean(GreetingService.class);
+                    assertThat(context).hasSingleBean(UserGreetingService.class);
+                });
+    }
+
+    @Test
+    void shouldNotUseStdOutGreetingServiceIfNotOnClasspath() {
+        this.contextRunner
+                .withPropertyValues("workshop.greeting.type=stdout")
+                .withClassLoader(new FilteredClassLoader(StdOutGreetingService.class))
+                .run(context -> {
+                    assertThat(context).doesNotHaveBean(GreetingService.class);
+                });
+    }
+
+    @Test
+    void shouldNotUseLoggerGreetingServiceIfNotOnClasspath() {
+        this.contextRunner
+                .withPropertyValues("workshop.greeting.type=logger")
+                .withClassLoader(new FilteredClassLoader(LoggerGreetingService.class))
+                .run(context -> {
+                    assertThat(context).doesNotHaveBean(GreetingService.class);
+                });
+    }
+
+    @Test
+    void shouldProvideBeepGreetingServiceIfSystemPropertyIsSet() {
+        this.contextRunner
+                .withPropertyValues("workshop.greeting.type=none")
+                .withSystemProperties("my.custom.condition=true")
+                .run(context -> {
+                    assertThat(context).hasSingleBean(BeepGreetingService.class);
+                });
+    }
+
+    @Test
+    void shouldNotUseBeepGreetingServiceIfNotOnClasspath() {
+        this.contextRunner
+                .withPropertyValues("workshop.greeting.type=none")
+                .withSystemProperties("my.custom.condition=true")
+                .withClassLoader(new FilteredClassLoader(BeepGreetingService.class))
+                .run(context -> {
+                    assertThat(context).doesNotHaveBean(GreetingService.class);
+                });
+    }
+
+    private static class UserGreetingService implements GreetingService {
+        @Override
+        public void greet(String name) {
+            System.out.println("UserGreetingService: Hello " + name);
+        }
+    }
+}