BAEL-4437 - System Rules

testing-modules/pom.xml

@@ -42,6 +42,7 @@
         <module>xmlunit-2</module>
         <module>junit-4</module>
 	<module>testing-libraries</module>
+	<module>testing-libraries-2</module>
         <module>powermock</module>
     </modules>
 

testing-modules/testing-libraries-2/pom.xml

@@ -0,0 +1,43 @@
+<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>
+    <artifactId>testing-libraries-2</artifactId>
+    <name>testing-libraries-2</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>testing-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.github.stefanbirkner</groupId>
+            <artifactId>system-rules</artifactId>
+            <version>${system-rules.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.github.stefanbirkner</groupId>
+            <artifactId>system-lambda</artifactId>
+            <version>${system-lambda.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>testing-libraries</finalName>
+        <resources>
+            <resource>
+                <directory>src/test/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+    </build>
+
+    <properties>
+        <system-rules.version>1.19.0</system-rules.version>
+        <system-lambda.version>1.0.0</system-lambda.version>
+    </properties>
+</project>

testing-modules/testing-libraries-2/src/test/java/com/baeldung/systemrules/ClearSystemPropertiesWithRuleUnitTest.java

@@ -0,0 +1,19 @@
+package com.baeldung.systemrules;
+
+import static org.junit.Assert.assertNull;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.contrib.java.lang.system.ClearSystemProperties;
+
+public class ClearSystemPropertiesWithRuleUnitTest {
+
+    @Rule
+    public final ClearSystemProperties userNameIsClearedRule = new ClearSystemProperties("user.name");
+
+    @Test
+    public void givenClearUsernameProperty_whenGetUserName_thenNull() {
+        assertNull(System.getProperty("user.name"));
+    }
+
+}

testing-modules/testing-libraries-2/src/test/java/com/baeldung/systemrules/ProvidesSystemPropertyUnitTest.java

@@ -0,0 +1,26 @@
+package com.baeldung.systemrules;
+
+import static com.github.stefanbirkner.systemlambda.SystemLambda.restoreSystemProperties;
+import static org.junit.Assert.assertEquals;
+
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+class ProvidesSystemPropertyUnitTest {
+
+    @BeforeAll
+    static void setUpBeforeClass() throws Exception {
+        System.setProperty("log_dir", "/tmp/baeldung/logs");
+    }
+
+    @Test
+    void givenSetSystemProperty_whenGetLogDir_thenLogDirIsProvidedSuccessfully() throws Exception {
+        restoreSystemProperties(() -> {
+            System.setProperty("log_dir", "test/resources");
+            assertEquals("log_dir should be provided", "test/resources", System.getProperty("log_dir"));
+        });
+
+        assertEquals("log_dir should be provided", "/tmp/baeldung/logs", System.getProperty("log_dir"));
+    }
+
+}

testing-modules/testing-libraries-2/src/test/java/com/baeldung/systemrules/ProvidesSystemPropertyWithRuleUnitTest.java

@@ -0,0 +1,44 @@
+package com.baeldung.systemrules;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.contrib.java.lang.system.ProvideSystemProperty;
+
+public class ProvidesSystemPropertyWithRuleUnitTest {
+
+    @Rule
+    public final ProvideSystemProperty providesSystemPropertyRule = new ProvideSystemProperty("log_dir", "test/resources").and("another_property", "another_value");
+
+    @Rule
+    public final ProvideSystemProperty providesSystemPropertyFromFileRule = ProvideSystemProperty.fromResource("/test.properties");
+
+    @BeforeClass
+    public static void setUpBeforeClass() {
+        setLogs();
+    }
+
+    @AfterClass
+    public static void tearDownAfterClass() throws Exception {
+        System.out.println(System.getProperty("log_dir"));
+    }
+
+    @Test
+    public void givenProvideSystemProperty_whenGetLogDir_thenLogDirIsProvidedSuccessfully() {
+        assertEquals("log_dir should be provided", "test/resources", System.getProperty("log_dir"));
+    }
+
+    @Test
+    public void givenProvideSystemPropertyFromFile_whenGetName_thenNameIsProvidedSuccessfully() {
+        assertEquals("name should be provided", "baeldung", System.getProperty("name"));
+        assertEquals("version should be provided", "1.0", System.getProperty("version"));
+    }
+
+    private static void setLogs() {
+        System.setProperty("log_dir", "/tmp/baeldung/logs");
+    }
+
+}

testing-modules/testing-libraries-2/src/test/java/com/baeldung/systemrules/SystemErrPrintlnUnitTest.java

@@ -0,0 +1,24 @@
+package com.baeldung.systemrules;
+
+import static com.github.stefanbirkner.systemlambda.SystemLambda.tapSystemErr;
+
+import org.junit.Assert;
+import org.junit.jupiter.api.Test;
+
+class SystemErrPrintlnUnitTest {
+
+    @Test
+    void givenTapSystemErr_whenInvokePrintln_thenOutputIsReturnedSuccessfully() throws Exception {
+
+        String text = tapSystemErr(() -> {
+            printError("An error occurred Baeldung Readers!!");
+        });
+
+        Assert.assertEquals("An error occurred Baeldung Readers!!", text.trim());
+    }
+
+    private void printError(String output) {
+        System.err.println(output);
+    }
+
+}

testing-modules/testing-libraries-2/src/test/java/com/baeldung/systemrules/SystemErrPrintlnWithRuleUnitTest.java

@@ -0,0 +1,25 @@
+package com.baeldung.systemrules;
+
+import org.junit.Assert;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.contrib.java.lang.system.SystemErrRule;
+
+public class SystemErrPrintlnWithRuleUnitTest {
+
+    @Rule
+    public final SystemErrRule systemErrRule = new SystemErrRule().enableLog();
+
+    @Test
+    public void givenSystemErrRule_whenInvokePrintln_thenLogSuccess() {
+        printError("An Error occurred Baeldung Readers!!");
+
+        Assert.assertEquals("An Error occurred Baeldung Readers!!", systemErrRule.getLog()
+            .trim());
+    }
+
+    private void printError(String output) {
+        System.err.println(output);
+    }
+
+}

testing-modules/testing-libraries-2/src/test/java/com/baeldung/systemrules/SystemExitUnitTest.java

@@ -0,0 +1,23 @@
+package com.baeldung.systemrules;
+
+import static org.junit.Assert.assertEquals;
+
+import static com.github.stefanbirkner.systemlambda.SystemLambda.catchSystemExit;
+
+import org.junit.jupiter.api.Test;
+
+class SystemExitUnitTest {
+
+    @Test
+    void givenCatchSystemExit_whenAppCallsSystemExit_thenStatusIsReturnedSuccessfully() throws Exception {
+        int statusCode = catchSystemExit(() -> {
+            exit();
+        });
+        assertEquals("status code should be 1:", 1, statusCode);
+    }
+
+    private void exit() {
+        System.exit(1);
+    }
+
+}

testing-modules/testing-libraries-2/src/test/java/com/baeldung/systemrules/SystemExitWithRuleUnitTest.java

@@ -0,0 +1,22 @@
+package com.baeldung.systemrules;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.contrib.java.lang.system.ExpectedSystemExit;
+
+public class SystemExitWithRuleUnitTest {
+
+    @Rule
+    public final ExpectedSystemExit exitRule = ExpectedSystemExit.none();
+
+    @Test
+    public void givenSystemExitRule_whenAppCallsSystemExit_thenExitRuleWorkssAsExpected() {
+        exitRule.expectSystemExitWithStatus(1);
+        exit();
+    }
+
+    private void exit() {
+        System.exit(1);
+    }
+
+}

testing-modules/testing-libraries-2/src/test/java/com/baeldung/systemrules/SystemInUnitTest.java

@@ -0,0 +1,27 @@
+package com.baeldung.systemrules;
+
+import static com.github.stefanbirkner.systemlambda.SystemLambda.withTextFromSystemIn;
+import static org.junit.Assert.assertEquals;
+
+import java.util.Scanner;
+
+import org.junit.jupiter.api.Test;
+
+class SystemInUnitTest {
+
+    @Test
+    void givenTwoNames_whenSystemInMock_thenNamesJoinedTogether() throws Exception {
+        withTextFromSystemIn("Jonathan", "Cook").execute(() -> {
+            assertEquals("Names should be concatenated", "Jonathan Cook", getFullname());
+        });
+    }
+
+    private String getFullname() {
+        try (Scanner scanner = new Scanner(System.in)) {
+            String firstName = scanner.next();
+            String surname = scanner.next();
+            return String.join(" ", firstName, surname);
+        }
+    }
+
+}

testing-modules/testing-libraries-2/src/test/java/com/baeldung/systemrules/SystemInWithRuleUnitTest.java

@@ -0,0 +1,31 @@
+package com.baeldung.systemrules;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Scanner;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.contrib.java.lang.system.TextFromStandardInputStream;
+import static org.junit.contrib.java.lang.system.TextFromStandardInputStream.emptyStandardInputStream;
+
+public class SystemInWithRuleUnitTest {
+
+    @Rule
+    public final TextFromStandardInputStream systemInMock = emptyStandardInputStream();
+
+    @Test
+    public void givenTwoNames_whenSystemInMock_thenNamesJoinedTogether() {
+        systemInMock.provideLines("Jonathan", "Cook");
+        assertEquals("Names should be concatenated", "Jonathan Cook", getFullname());
+    }
+
+    private String getFullname() {
+        try (Scanner scanner = new Scanner(System.in)) {
+            String firstName = scanner.next();
+            String surname = scanner.next();
+            return String.join(" ", firstName, surname);
+        }
+    }
+
+}

testing-modules/testing-libraries-2/src/test/resources/test.properties

@@ -0,0 +1,2 @@
+name=baeldung
+version=1.0