Add requirement that markdown cannot be generated with empty changes

version: 0.7.0
tag: Added

.travis.yml

@@ -9,8 +9,8 @@ before_install:
 - openssl aes-256-cbc -pass pass:$ENCRYPTION_PASSWORD -in credentials.sbt.enc -out local.credentials.sbt -d
 script:
 - sbt clean coverage test coverageReport coverageAggregate
-after_success:
 - sbt coveralls
+- sbt clean compile
 - sbt "+ publish-signed"
 - sbt "+ sonatypeRelease"
 env:

build.sbt

@@ -2,7 +2,7 @@ name := "sct"
 
 organization := "com.github.bzumhagen"
 
-version := "0.6.0"
+version := "0.7.0"
 
 scalaVersion := "2.12.1"
 
@@ -31,8 +31,6 @@ def betterFiles(scalaVersion: String) = scalaVersion match {
   case _         => "com.github.pathikrit" %% "better-files" % "2.17.0"
 }
 
-coverageEnabled := true
-
 pgpSecretRing := file("local.secring.asc")
 
 pgpPublicRing := file("local.pubring.asc")

src/main/scala/com/github/bzumhagen/sct/git/GitChangelog.scala

@@ -26,6 +26,8 @@ class GitChangelog(val config: ChangelogConfiguration, val gitDir: File) extends
   }
 
   override def generateMarkdown(file: File, changes: Seq[ChangelogChange]): File = {
+    require(changes.nonEmpty, "Cannot generate markdown without changes")
+
     val engine = new TemplateEngine
     val changeBindings = buildChangeBindings(changes)
     val nameBinding = Map("name" -> config.name)
@@ -72,8 +74,7 @@ class GitChangelog(val config: ChangelogConfiguration, val gitDir: File) extends
       case _ => None
     }
 
-  private def buildChangeBindings(
-      changes: Seq[ChangelogChange]): Map[String, Any] =
+  private def buildChangeBindings(changes: Seq[ChangelogChange]): Map[String, Any] =
     if (config.smartGrouping) {
       val latestVersion = changes.maxBy(_.version).version
       val latestPatchChanges = changes.filter { change =>

src/test/scala/com/github/bzumhagen/sct/git/GitChangelogTest.scala

@@ -199,4 +199,13 @@ class GitChangelogTest extends FlatSpec with Matchers {
     val actualChanges = gitChangelog.getChanges
     gitChangelog.generateMarkdown(changelogFile, actualChanges).contentAsString shouldBe expectedMarkdown
   }
+
+  it should "fail if no changes are provided to markdown generation" in {
+    val gitChangelog = new GitChangelog(DefaultConfiguration, File.newTemporaryDirectory())
+    val changelogFile = File.newTemporaryFile("changelogTestFile")
+
+    assertThrows[IllegalArgumentException] {
+      gitChangelog.generateMarkdown(changelogFile, Seq())
+    }
+  }
 }