[BAEL-1626] testing-modules | A Quick Guide to @TestPropertySource (#5255)

* *added tests using testpropertysource

* fix: using property for version in pom file

* fix, added dependency with compile scope to build successfully on mvn clean install

testing-modules/spring-context-testing/pom.xml

@@ -0,0 +1,25 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung</groupId>
+    <artifactId>spring-context-testing</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter</artifactId>
+            <version>${spring.boot.starter.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+            <version>${spring.boot.starter.version}</version>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <spring.boot.starter.version>2.0.4.RELEASE</spring.boot.starter.version>
+    </properties>
+</project>

testing-modules/spring-context-testing/src/main/java/com/baeldung/testpropertysource/ClassUsingProperty.java

@@ -0,0 +1,15 @@
+package com.baeldung.testpropertysource;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Component;
+
+@Component
+public class ClassUsingProperty {
+    
+    @Value("${baeldung.testpropertysource.one}")
+    private String propertyOne;
+    
+    public String retrievePropertyOne() {
+        return propertyOne;
+    }
+}

testing-modules/spring-context-testing/src/test/java/com/baeldung/testpropertysource/DefaultTestPropertySourceIntegrationTest.java

@@ -0,0 +1,26 @@
+package com.baeldung.testpropertysource;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.TestPropertySource;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@ContextConfiguration(classes = ClassUsingProperty.class)
+@TestPropertySource
+public class DefaultTestPropertySourceIntegrationTest {
+
+    @Autowired
+    ClassUsingProperty classUsingProperty;
+
+    @Test
+    public void givenDefaultTestPropertySource_whenVariableOneRetrieved_thenValueInDefaultFileReturned() {
+        String output = classUsingProperty.retrievePropertyOne();
+
+        assertThat(output).isEqualTo("default-value");
+    }
+}

testing-modules/spring-context-testing/src/test/java/com/baeldung/testpropertysource/LocationTestPropertySourceIntegrationTest.java

@@ -0,0 +1,26 @@
+package com.baeldung.testpropertysource;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.TestPropertySource;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@ContextConfiguration(classes = ClassUsingProperty.class)
+@TestPropertySource(locations = "/other-location.properties")
+public class LocationTestPropertySourceIntegrationTest {
+
+    @Autowired
+    ClassUsingProperty classUsingProperty;
+
+    @Test
+    public void givenDefaultTestPropertySource_whenVariableOneRetrieved_thenValueInDefaultFileReturned() {
+        String output = classUsingProperty.retrievePropertyOne();
+
+        assertThat(output).isEqualTo("other-location-value");
+    }
+}

testing-modules/spring-context-testing/src/test/java/com/baeldung/testpropertysource/PropertiesTestPropertySourceIntegrationTest.java

@@ -0,0 +1,26 @@
+package com.baeldung.testpropertysource;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.TestPropertySource;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@ContextConfiguration(classes = ClassUsingProperty.class)
+@TestPropertySource(locations = "/other-location.properties", properties = "baeldung.testpropertysource.one=other-properties-value")
+public class PropertiesTestPropertySourceIntegrationTest {
+
+    @Autowired
+    ClassUsingProperty classUsingProperty;
+
+    @Test
+    public void givenDefaultTestPropertySource_whenVariableOneRetrieved_thenValueInDefaultFileReturned() {
+        String output = classUsingProperty.retrievePropertyOne();
+
+        assertThat(output).isEqualTo("other-properties-value");
+    }
+}

testing-modules/spring-context-testing/src/test/resources/com/baeldung/testpropertysource/DefaultTestPropertySourceIntegrationTest.properties

@@ -0,0 +1 @@
+baeldung.testpropertysource.one=default-value

testing-modules/spring-context-testing/src/test/resources/other-location.properties

@@ -0,0 +1 @@
+baeldung.testpropertysource.one=other-location-value