Restore the default starter if none is set

This commit fixes a regression introduced by the library refactoring.

Previously, if no dependency was selected, the default
'spring-boot-starter' was added to provide the necessary base
dependencies.

This commit adds a addDefaultDependency on ProjectRequest that
adds that dependency. It can be overridden if the default needs to be
different.

Fixes gh-34

initializr/src/main/groovy/io/spring/initializr/InitializrMetadata.groovy

@@ -25,6 +25,7 @@ import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 
 import org.springframework.boot.context.properties.ConfigurationProperties
+import org.springframework.util.StringUtils
 
 /**
  * The metadata using by the initializr, that is:
@@ -218,10 +219,11 @@ class InitializrMetadata {
 
 		/**
 		 * Define this dependency as a standard spring boot starter with the specified name
+		 * <p>If no name is specified, the root 'spring-boot-starter' is assumed.
 		 */
 		def asSpringBootStarter(String name) {
 			groupId = 'org.springframework.boot'
-			artifactId = 'spring-boot-starter-' + name
+			artifactId = StringUtils.hasText(name) ? 'spring-boot-starter-' + name : 'spring-boot-starter'
 		}
 
 		/**

initializr/src/main/groovy/io/spring/initializr/ProjectRequest.groovy

@@ -88,6 +88,21 @@ class ProjectRequest {
 			dependencies << metadata.getDependency('web')
 			facets << 'web'
 		}
+		if (dependencies.isEmpty()) {
+			addDefaultDependency()
+		}
+	}
+
+	/**
+	 * Add a default dependency if the project does not define any
+	 * dependency
+	 */
+	protected addDefaultDependency() {
+		InitializrMetadata.Dependency root = new InitializrMetadata.Dependency()
+		root.id = 'root_starter'
+		root.asSpringBootStarter('')
+		dependencies << root
+
 	}
 
 	/**

initializr/src/test/groovy/io/spring/initializr/ProjectGeneratorTests.groovy

@@ -77,6 +77,13 @@ class ProjectGeneratorTests {
 		verify(listener, times(1)).onGeneratedProject(request)
 	}
 
+	@Test
+	void noDependencyAddsRootStarter() {
+		ProjectRequest request = createProjectRequest()
+		generateProject(request).isJavaProject().isMavenProject().pomAssert()
+				.hasSpringBootStarterRootDependency()
+	}
+
 	@Test
 	void mavenPomWithBootSnapshot() {
 		ProjectRequest request = createProjectRequest('web')

initializr/src/test/groovy/io/spring/initializr/support/PomAssert.groovy

@@ -113,6 +113,10 @@ class PomAssert {
 		hasDependency('org.springframework.boot', 'spring-boot-starter-' + dependency)
 	}
 
+	PomAssert hasSpringBootStarterRootDependency() {
+		hasDependency('org.springframework.boot', 'spring-boot-starter')
+	}
+
 	PomAssert hasDependency(String groupId, String artifactId) {
 		hasDependency(groupId, artifactId, null)
 	}

initializr/src/test/groovy/io/spring/initializr/web/AbstractInitializerControllerFormIntegrationTests.groovy

@@ -66,7 +66,8 @@ abstract class AbstractInitializerControllerFormIntegrationTests extends Abstrac
 		HomePage page = home()
 		ProjectAssert projectAssert = zipProjectAssert(page.generateProject())
 		projectAssert.isMavenProject().isJavaProject().hasStaticAndTemplatesResources(false)
-				.pomAssert().hasDependenciesCount(1).hasSpringBootStarterDependency('test')
+				.pomAssert().hasDependenciesCount(2)
+				.hasSpringBootStarterRootDependency().hasSpringBootStarterDependency('test')
 	}
 
 	@Test

initializr/src/test/groovy/io/spring/initializr/web/MainControllerIntegrationTests.groovy

@@ -57,6 +57,15 @@ class MainControllerIntegrationTests extends AbstractInitializrControllerIntegra
 				.hasDependency('org.acme', 'bar', '2.1.0')
 	}
 
+	@Test
+	void noDependencyProject() {
+		downloadZip('/starter.zip').isJavaProject().isMavenProject()
+				.hasStaticAndTemplatesResources(false).pomAssert()
+				.hasDependenciesCount(2)
+				.hasSpringBootStarterRootDependency() // the root dep is added if none is specified
+				.hasSpringBootStarterDependency('test')
+	}
+
 	@Test
 	void gradleWarProject() {
 		downloadZip('/starter.zip?style=web&style=security&packaging=war&type=gradle.zip')