Return singular graph on modules without dependencies

plugin/src/main/kotlin/com/jraska/module/graph/assertion/GradleDependencyGraphFactory.kt

@@ -7,31 +7,38 @@ import org.gradle.api.Project
 object GradleDependencyGraphFactory {
 
   fun create(project: Project, configurationsToLook: Set<String>): DependencyGraph {
-    val dependencies = project.listAllDependencyPairs(configurationsToLook)
+    val modulesWithDependencies = project.listAllDependencies(configurationsToLook)
+    val dependencies = modulesWithDependencies.flatMap { module ->
+      module.second.map { module.first to it }
+    }
 
-    if (dependencies.isEmpty()) {
-      return DependencyGraph.createSingular(project.moduleDisplayName())
+    val moduleDisplayName = project.moduleDisplayName()
+    if(dependencies.isEmpty()) {
+      return DependencyGraph.createSingular(moduleDisplayName)
     }
 
     val fullDependencyGraph = DependencyGraph.create(dependencies)
 
-    return if (project == project.rootProject) {
-      fullDependencyGraph
-    } else {
-      fullDependencyGraph.subTree(project.moduleDisplayName())
+    if (project == project.rootProject) {
+      return fullDependencyGraph
     }
+
+    modulesWithDependencies.find { it.first == moduleDisplayName && it.second.isNotEmpty() }
+      ?: return DependencyGraph.createSingular(moduleDisplayName)
+
+    return fullDependencyGraph.subTree(moduleDisplayName)
   }
 
-  private fun Project.listAllDependencyPairs(configurationsToLook: Set<String>): List<Pair<String, String>> {
+  private fun Project.listAllDependencies(configurationsToLook: Set<String>): List<Pair<String, List<String>>> {
     return rootProject.subprojects
-      .flatMap { project ->
-        project.configurations
+      .map { project ->
+        project.moduleDisplayName() to project.configurations
           .filter { configurationsToLook.contains(it.name) }
           .flatMap { configuration ->
             configuration.dependencies.filterIsInstance(ProjectDependency::class.java)
               .map { it.dependencyProject }
           }
-          .map { project.moduleDisplayName() to it.moduleDisplayName() }
+          .map { it.moduleDisplayName() }
       }
   }
 }

plugin/src/test/kotlin/com/jraska/module/graph/assertion/FullProjectMultipleAppliedGradleTest.kt

@@ -0,0 +1,83 @@
+package com.jraska.module.graph.assertion
+
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.TemporaryFolder
+import java.io.File
+
+class FullProjectMultipleAppliedGradleTest {
+  @get:Rule
+  val testProjectDir: TemporaryFolder = TemporaryFolder()
+
+  @Before
+  fun setup() {
+    testProjectDir.newFile("settings.gradle")
+      .writeText("include ':app', ':core', 'core-api', 'no-dependencies'")
+
+    createModule(
+      "core-api", content = """
+      apply plugin: 'java-library'
+      """
+    )
+
+    createModule(
+      "core", content = """
+      apply plugin: 'java-library'
+
+      dependencies {
+        implementation project(":core-api")
+      }
+      """
+    )
+
+    createModule(
+      "app", content = """
+          plugins {
+              id 'com.jraska.module.graph.assertion'
+          }
+          apply plugin: 'java-library'
+
+          moduleGraphAssert {
+            maxHeight = 2
+          }
+
+          dependencies {
+            implementation project(":core-api")
+            implementation project(":core")
+          }
+      """
+    )
+
+    createModule(
+      "no-dependencies", content = """
+          plugins {
+              id 'com.jraska.module.graph.assertion'
+          }
+          apply plugin: 'java-library'
+
+          moduleGraphAssert {
+            maxHeight = 0
+          }
+      """
+    )
+  }
+
+  @Test
+  fun printsBothCorrectStatistics() {
+    val output =
+      runGradleAssertModuleGraph(testProjectDir.root, "generateModulesGraphStatistics").output
+
+    println(output)
+    assert(output.contains("> Task :app:generateModulesGraphStatistics\n" +
+      "GraphStatistics(modulesCount=3, edgesCount=3, height=2, longestPath=':app -> :core -> :core-api')\n" +
+      "\n" +
+      "> Task :no-dependencies:generateModulesGraphStatistics\n" +
+      "GraphStatistics(modulesCount=1, edgesCount=0, height=0, longestPath=':no-dependencies')"))
+  }
+
+  private fun createModule(dir: String, content: String) {
+    val newFolder = testProjectDir.newFolder(dir)
+    File(newFolder, "build.gradle").writeText(content)
+  }
+}