Use 'spotless' ktlin code linter and formatter

https://github.com/diffplug/spotless
https://github.com/diffplug/spotless/tree/master/plugin-gradle

README.md

@@ -32,6 +32,10 @@ An executable file named `pullpitoK` should be generated in the current director
 
 ## Dev tasks
 
+### Format the code
+
+    ./gradlew spotlessApply
+
 ### Inspect the code
 
 Code inspection is configured on the master branch. See the [sonarcloud.io's dashboard](https://sonarcloud.io/dashboard?id=nicokosi_pullpitoK).

build.gradle.kts

@@ -6,6 +6,7 @@ plugins {
     id("com.github.ben-manes.versions") version "0.28.0"
     id("com.github.johnrengelman.shadow") version "5.2.0"
     id("com.adarshr.test-logger") version "2.0.0"
+    id("com.diffplug.gradle.spotless") version "4.5.1"
     application
 }
 
@@ -42,3 +43,14 @@ tasks.withType<DependencyUpdatesTask> {
         }
     }
 }
+
+spotless {
+    kotlin {
+        ktlint()
+    }
+    kotlinGradle {
+        // same as kotlin, but for .gradle.kts files (defaults to '*.gradle.kts')
+        target("*.gradle.kts")
+        ktlint()
+    }
+}

src/main/kotlin/pullpitok/App.kt

@@ -1,10 +1,10 @@
 package pullpitok
 
+import kotlin.system.exitProcess
 import pullpitok.github.Action
 import pullpitok.github.Event
 import pullpitok.github.EventClient
 import pullpitok.github.Type
-import kotlin.system.exitProcess
 
 fun main(args: Array<String>) {
     if (invalidArguments(args)) {
@@ -44,8 +44,9 @@ private fun perAuthor(events: List<Event>): Map<String, List<Event>> = events
         .groupBy { it.actor.login }
 
 internal fun counters(
-        eventsPerAuthor: Map<String, List<Event>>,
-        predicate: (Event) -> Boolean): String {
+    eventsPerAuthor: Map<String, List<Event>>,
+    predicate: (Event) -> Boolean
+): String {
     eventsPerAuthor.entries
     var counters = ""
     for (events in eventsPerAuthor.entries) {

src/main/kotlin/pullpitok/github/EventClient.kt

@@ -39,5 +39,4 @@ class EventClient {
     }
 
     private fun fail(message: String): Nothing = throw IllegalArgumentException(message)
-
 }

src/test/kotlin/pullpitok/AppTest.kt

@@ -1,12 +1,12 @@
 package pullpitok
 
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
 import org.junit.Test
 import pullpitok.github.Actor
 import pullpitok.github.Event
 import pullpitok.github.Payload
-import kotlin.test.assertEquals
-import kotlin.test.assertFalse
-import kotlin.test.assertTrue
 
 class AppTest {
 
@@ -38,5 +38,4 @@ class AppTest {
         assertFalse(invalidArguments(arrayOf("org/repo")))
         assertFalse(invalidArguments(arrayOf("org/repo", "token")))
     }
-
 }

src/test/kotlin/pullpitok/github/EventClientTest.kt

@@ -1,7 +1,7 @@
 package pullpitok.github
 
-import org.junit.Test
 import kotlin.test.assertEquals
+import org.junit.Test
 
 class EventClientTest {
 
@@ -28,5 +28,4 @@ class EventClientTest {
     }
 
     private fun loadJsonEventFile() = EventClientTest::class.java.getResource("/events.json").readText()
-
 }