Fix ClojureRun task creation: converting the fn property from abstract to a concrete implementation

src/main/groovy/nebula/plugin/clojuresque/tasks/ClojureRun.groovy

@@ -19,13 +19,17 @@ abstract class ClojureRun extends ClojureSourceTask {
     @Classpath
     abstract ConfigurableFileCollection getClasspath()
 
+    private final Property<String> fn
+
     @Input
     @Optional
-    abstract Property<String> getFn()
+    Property<String> getFn() {
+        return fn
+    }
 
     @Option(option = "fn", description = "The clojure function (and optional args) to execute.")
     public void setFn(String fn) {
-        this.getFn().set(fn)
+        this.fn.set(fn)
     }
 
     private final ExecOperations execOperations
@@ -39,6 +43,7 @@ abstract class ClojureRun extends ClojureSourceTask {
     ClojureRun(ExecOperations execOperations, ObjectFactory objects) {
         this.execOperations = execOperations
         this.objects = objects
+        this.fn = objects.property(String)
     }
 
     void jvmOptions(Closure closure) {
@@ -50,7 +55,7 @@ abstract class ClojureRun extends ClojureSourceTask {
     void run() {
 
         def options = [
-            fn: fn.getOrNull()
+            fn: getFn().getOrNull()
         ]
 
         def runtime = [

src/test/groovy/nebula/plugin/clojure/ClojureRunSpec.groovy

@@ -0,0 +1,136 @@
+package nebula.plugin.clojure
+
+class ClojureRunSpec extends BaseIntegrationTestKitSpec {
+
+    private final APP_CLJ = '''\
+            (ns test.nebula.app)
+
+            (defn hello
+              [name]
+              (println "Hello," name))
+
+            (defn greet-world
+              []
+              (println "Hello, World!"))
+            '''.stripIndent()
+
+    def 'clojureRun task can be created and registered'() {
+        given:
+        buildFile << '''\
+            plugins {
+                id 'com.netflix.nebula.clojure'
+            }
+
+            repositories { mavenCentral() }
+
+            dependencies {
+                implementation 'org.clojure:clojure:1.10.3'
+            }
+            '''.stripIndent()
+
+        settingsFile << 'rootProject.name="clojure-run-test"'
+
+        def clojurefiles = new File(projectDir, 'src/main/clojure/test/nebula')
+        clojurefiles.mkdirs()
+        new File(clojurefiles, 'app.clj').text = APP_CLJ
+
+        when:
+        def result = runTasks('tasks', '--all')
+
+        then:
+        noExceptionThrown()
+        result.output.contains('clojureRun')
+    }
+
+    def 'clojureRun task accepts --fn command line option'() {
+        given:
+        buildFile << '''\
+            plugins {
+                id 'com.netflix.nebula.clojure'
+            }
+
+            repositories { mavenCentral() }
+
+            dependencies {
+                implementation 'org.clojure:clojure:1.10.3'
+            }
+            '''.stripIndent()
+
+        settingsFile << 'rootProject.name="clojure-run-with-fn"'
+
+        def clojurefiles = new File(projectDir, 'src/main/clojure/test/nebula')
+        clojurefiles.mkdirs()
+        new File(clojurefiles, 'app.clj').text = APP_CLJ
+
+        when:
+        def result = runTasks('clojureRun', '--fn=test.nebula.app/greet-world')
+
+        then:
+        noExceptionThrown()
+        result.output.contains('Hello, World!')
+    }
+
+    def 'clojureRun task can be configured with fn property'() {
+        given:
+        buildFile << '''\
+            plugins {
+                id 'com.netflix.nebula.clojure'
+            }
+
+            repositories { mavenCentral() }
+
+            dependencies {
+                implementation 'org.clojure:clojure:1.10.3'
+            }
+
+            tasks.named('clojureRun') {
+                fn = 'test.nebula.app/greet-world'
+            }
+            '''.stripIndent()
+
+        settingsFile << 'rootProject.name="clojure-run-configured"'
+
+        def clojurefiles = new File(projectDir, 'src/main/clojure/test/nebula')
+        clojurefiles.mkdirs()
+        new File(clojurefiles, 'app.clj').text = APP_CLJ
+
+        when:
+        def result = runTasks('clojureRun')
+
+        then:
+        noExceptionThrown()
+        result.output.contains('Hello, World!')
+    }
+
+    def 'clojureRun task works with fn property using Provider API'() {
+        given:
+        buildFile << '''\
+            plugins {
+                id 'com.netflix.nebula.clojure'
+            }
+
+            repositories { mavenCentral() }
+
+            dependencies {
+                implementation 'org.clojure:clojure:1.10.3'
+            }
+
+            tasks.named('clojureRun') {
+                fn.set('test.nebula.app/greet-world')
+            }
+            '''.stripIndent()
+
+        settingsFile << 'rootProject.name="clojure-run-provider-api"'
+
+        def clojurefiles = new File(projectDir, 'src/main/clojure/test/nebula')
+        clojurefiles.mkdirs()
+        new File(clojurefiles, 'app.clj').text = APP_CLJ
+
+        when:
+        def result = runTasks('clojureRun')
+
+        then:
+        noExceptionThrown()
+        result.output.contains('Hello, World!')
+    }
+}