add unit tests

build.gradle.kts

@@ -20,10 +20,17 @@ repositories {
     mavenCentral()
 }
 
+val test by tasks.getting(Test::class) {
+    useJUnitPlatform { }
+}
+
 dependencies {
+    compile("com.moandjiezana.toml:toml4j:0.7.2")
     implementation(kotlin("stdlib-jdk8"))
     implementation("org.javacord:javacord:3.0.4")
-    compile("com.moandjiezana.toml:toml4j:0.7.2")
+
+    testImplementation("io.kotlintest:kotlintest-runner-junit5:3.3.2")
+    testImplementation("io.mockk:mockk:1.9")
 }
 
 tasks.withType<KotlinCompile> {

src/test/kotlin/moe/kageru/kagebot/CommandTest.kt

@@ -1,2 +1,28 @@
 package moe.kageru.kagebot
 
+import io.kotlintest.shouldBe
+import io.kotlintest.specs.StringSpec
+
+class CommandTest : StringSpec({
+    "should match prefix command" {
+        testMessage("!ping", "pong")
+    }
+    "should match contains command" {
+        testMessage("the trigger is somewhere in this message", "found it")
+    }
+    "should match regex command" {
+        testMessage("AcsdB", "regex matched")
+    }
+    "should ping author" {
+        testMessage("answer me", "<@1> there you go")
+    }
+}) {
+    companion object {
+        fun testMessage(content: String, result: String) {
+            val calls = mutableListOf<String>()
+            Kagebot.processMessage(TestUtil.mockMessage(content, capturedCalls = calls))
+            calls.size shouldBe 1
+            calls[0] shouldBe result
+        }
+    }
+}

src/test/kotlin/moe/kageru/kagebot/ConfigTest.kt

@@ -1,2 +1,10 @@
 package moe.kageru.kagebot
 
+import io.kotlintest.shouldNotBe
+import io.kotlintest.specs.StringSpec
+
+class ConfigTest : StringSpec({
+    "should properly parse default config" {
+        Config.config shouldNotBe null
+    }
+})

src/test/kotlin/moe/kageru/kagebot/TestUtil.kt

@@ -1,2 +1,15 @@
 package moe.kageru.kagebot
 
+import io.mockk.every
+import io.mockk.mockk
+import org.javacord.api.event.message.MessageCreateEvent
+
+object TestUtil {
+    fun mockMessage(content: String, author: Long = 1, capturedCalls: MutableList<String> = mutableListOf()): MessageCreateEvent {
+        val message = mockk<MessageCreateEvent>()
+        every { message.messageContent } returns content
+        every { message.messageAuthor.id } returns author
+        every { message.channel.sendMessage(capture(capturedCalls)) } returns mockk()
+        return message
+    }
+}