Add -DdepsTreeOutputFile system property for Projects command

src/main/java/com/jfrog/mavendeptree/MavenProjectTree.java

@@ -2,12 +2,16 @@
 
 import org.apache.maven.artifact.Artifact;
 import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
 import org.apache.maven.plugins.annotations.Mojo;
 import org.apache.maven.plugins.annotations.Parameter;
 
 import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
 
 import static com.jfrog.mavendeptree.Utils.getGavString;
+import static java.lang.System.lineSeparator;
 
 /**
  * @author yahavi
@@ -24,11 +28,30 @@ public class MavenProjectTree extends AbstractMojo {
     @Parameter(property = "project.file")
     private File file;
 
+    // Specify the system property to an empty file, where the projects command output will be written
+    @Parameter(property = "depsTreeOutputFile", readonly = true)
+    private File depsTreeOutputFile;
+
     @Override
-    public void execute() {
+    public void execute() throws MojoExecutionException {
         String gav = getGavString(artifact);
         String parentGav = getGavString(parent);
         String pomPath = file.getAbsolutePath();
-        System.out.printf("{\"gav\":\"%s\",\"parentGav\":\"%s\",\"pomPath\":\"%s\"}%n", gav, parentGav, pomPath);
+        String projectInfo = String.format(
+                "{\"gav\":\"%s\",\"parentGav\":\"%s\",\"pomPath\":\"%s\"}",
+                gav, parentGav, pomPath
+        );
+
+        if (depsTreeOutputFile == null) {
+            System.out.println(projectInfo);
+            return;
+        }
+
+        try (FileWriter fileWriter = new FileWriter(depsTreeOutputFile, true)) {
+            fileWriter.append(projectInfo).append(lineSeparator());
+        } catch (IOException e) {
+            String errorMessage = "Error writing to depsTreeOutputFile: " + e.getMessage();
+            throw new MojoExecutionException(errorMessage, e);
+        }
     }
 }

src/test/java/com/jfrog/mavendeptree/integration/MavenProjectTreeITest.java

@@ -1,5 +1,6 @@
 package com.jfrog.mavendeptree.integration;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
 import lombok.Setter;
@@ -23,11 +24,24 @@ public class MavenProjectTreeITest {
     @Test
     public void testMultiModule() throws VerificationException, IOException {
         // Run Mojo
-        List<String> projectInfos = runMavenProjectTree("multi-module", pluginVersion);
+        List<String> projectInfos = runMavenProjectTree("multi-module", pluginVersion, false);
 
         // Test output
-        assertEquals(projectInfos.size(), 4);
-        for (String projectInfoJson : projectInfos) {
+       verifyTestMultiModuleResults(projectInfos);
+    }
+
+    @Test
+    public void testMultiModuleWithOutputFile() throws VerificationException, IOException {
+        // Run Mojo
+        List<String> projectInfos = runMavenProjectTree("multi-module", pluginVersion, true);
+
+        // Test output
+        verifyTestMultiModuleResults(projectInfos);
+    }
+
+    private void verifyTestMultiModuleResults(List<String> testResults) throws JsonProcessingException {
+        assertEquals(testResults.size(), 4);
+        for (String projectInfoJson : testResults) {
             ProjectInfo projectInfo = mapper.readValue(escapePathInWindows(projectInfoJson), ProjectInfo.class);
             switch (projectInfo.getGav()) {
                 case "org.jfrog.test:multi:3.7-SNAPSHOT":
@@ -64,7 +78,7 @@ public void testMavenArchetypeDependencyManagement() throws VerificationExceptio
 
     private void testMavenArchetype(String projectName) throws VerificationException, IOException {
         // Run Mojo
-        List<String> projectInfoJson = runMavenProjectTree(projectName, pluginVersion);
+        List<String> projectInfoJson = runMavenProjectTree(projectName, pluginVersion, false);
 
         // Test output
         assertEquals(projectInfoJson.size(), 1);

src/test/java/com/jfrog/mavendeptree/integration/Utils.java

@@ -15,6 +15,7 @@
 import java.io.File;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.List;
@@ -74,18 +75,37 @@ static List<String> runMavenDepTree(String projectName, String testOutputDir, St
      *
      * @param projectName   - The test project to run
      * @param pluginVersion - The plugin version
+     * @param withOutputFile - Write the test result to a temporary output file
      * @return the output.
      * @throws IOException           in case of any unexpected I/O error.
      * @throws VerificationException in case of any Maven Verifier error.
      */
-    static List<String> runMavenProjectTree(String projectName, String pluginVersion) throws IOException, VerificationException {
+    static List<String> runMavenProjectTree(String projectName, String pluginVersion, Boolean withOutputFile) throws IOException, VerificationException {
         File testDir = ResourceExtractor.simpleExtractResources(Utils.class, "/integration/" + projectName);
         Verifier verifier = new Verifier(testDir.getAbsolutePath());
+
         if (StringUtils.equalsIgnoreCase(System.getProperty("debugITs"), "true")) {
             verifier.setEnvironmentVariable("MAVEN_OPTS", "-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=5005");
         }
-        verifier.executeGoals(Lists.newArrayList("clean", "com.jfrog:maven-dep-tree:" + pluginVersion + ":projects", "-q"));
+
+        String outputFile = verifier.getLogFileName();
+        List<String> goals = Lists.newArrayList("clean", "com.jfrog:maven-dep-tree:" + pluginVersion + ":projects", "-q");
+
+        if (withOutputFile) {
+            Path tempFile = Files.createTempFile(Paths.get(testDir.getAbsolutePath()), "testOutput", ".out");
+            String tempFilePath = tempFile.toAbsolutePath().toString();
+            goals.add("-DdepsTreeOutputFile=" + tempFilePath);
+            outputFile = Paths.get(tempFilePath).getFileName().toString();
+        }
+
+        verifier.executeGoals(goals);
         verifier.verifyErrorFreeLog();
-        return verifier.loadFile(verifier.getBasedir(), verifier.getLogFileName(), false);
+        List<String> results = verifier.loadFile(verifier.getBasedir(), outputFile, false);
+
+        if (withOutputFile) {
+            Files.deleteIfExists(Paths.get(testDir.getAbsolutePath(), outputFile));
+        }
+
+        return results;
     }
 }