diff --git a/src/main/kotlin/alfred/web/core/Processes.kt b/src/main/kotlin/alfred/web/core/Processes.kt
index 6923792..2f0b7ad 100644
--- a/src/main/kotlin/alfred/web/core/Processes.kt
+++ b/src/main/kotlin/alfred/web/core/Processes.kt
@@ -17,4 +17,10 @@ class Processes {
                 environment()["ALFRED_REV"] = rev
             }
 
+    fun startThread(block: () -> Unit) {
+        Thread {
+            block()
+        }.start()
+    }
+
 }
diff --git a/src/main/kotlin/alfred/web/core/build/Workspaces.kt b/src/main/kotlin/alfred/web/core/build/Workspaces.kt
index 3892a82..b8cac99 100644
--- a/src/main/kotlin/alfred/web/core/build/Workspaces.kt
+++ b/src/main/kotlin/alfred/web/core/build/Workspaces.kt
@@ -10,7 +10,7 @@ import kotlin.io.deleteRecursively
 @Service
 class Workspaces {
 
-    fun withWorkspace(ctx: BuildContext, block: (Path) -> Unit) {
+    fun withWorkspace(ctx: BuildContext, block: (Workspace) -> Unit) {
         val wsDir = prepare(ctx)
 
         try {
@@ -20,7 +20,7 @@ class Workspaces {
         }
     }
 
-    fun prepare(ctx: BuildContext): Path {
+    fun prepare(ctx: BuildContext): Workspace {
         val workspacePath = Paths.get(
             ctx.config.workspace, UUID.randomUUID().toString()
         )
@@ -40,15 +40,14 @@ class Workspaces {
         return workspacePath
     }
 
-    fun cleanUp(wsDir: Path) {
+    fun cleanUp(wsDir: Workspace) {
         wsDir.toFile().deleteRecursively()
     }
 
 }
 
+typealias Workspace = Path
+
 class WorkspaceIsNotEmpty(
     private val ws: String
-) : RuntimeException() {
-    override fun toString() =
-        "${this::class}: workspace $ws is not empty"
-}
+) : RuntimeException("${WorkspaceIsNotEmpty::class}: workspace $ws is not empty")
diff --git a/src/main/kotlin/alfred/web/core/runner/GitRunner.kt b/src/main/kotlin/alfred/web/core/runner/GitRunner.kt
index d0bf8e5..88ffbeb 100644
--- a/src/main/kotlin/alfred/web/core/runner/GitRunner.kt
+++ b/src/main/kotlin/alfred/web/core/runner/GitRunner.kt
@@ -7,11 +7,11 @@ import alfred.web.core.build.BuildContext
 import alfred.web.core.build.BuildId
 import alfred.web.core.build.Builds
 import alfred.web.core.build.ProcessInfo
+import alfred.web.core.build.Workspace
 import alfred.web.core.build.Workspaces
 import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 import org.springframework.stereotype.Service
-import java.nio.file.Path
 import java.util.concurrent.TimeUnit
 import kotlin.collections.forEach
 import kotlin.jvm.java
@@ -26,6 +26,8 @@ class GitRunner(
 
     val scriptsDir = ".alfred"
 
+    val scriptFiles = listOf("pre.sh", "job.sh", "post.sh")
+
     fun run(buildId: BuildId, rev: String): ProcessInfo {
         val config = builds.buildConfig(buildId)
         val logFile = builds.createLogFile(buildId)
@@ -40,54 +42,56 @@ class GitRunner(
             rev = rev
         )
 
-        Thread {
+        processes.startThread {
             workspaces.withWorkspace(ctx) { wsPath ->
                 logFile.header(buildId, rev, wsPath)
 
                 clone(ctx, wsPath)
+                checkout(ctx, wsPath)
                 execScripts(ctx, wsPath)
 
                 logFile.footer()
             }
-        }.start()
+        }
 
         return ProcessInfo(-1, logFile)
     }
 
-    private fun clone(ctx: BuildContext, wsPath: Path) {
-        ctx.log("build ${ctx.buildId}: cloning ${ctx.config.gitRepo} into $wsPath")
+    private fun clone(ctx: BuildContext, ws: Workspace) {
+        ctx.log("build ${ctx.buildId}: cloning ${ctx.config.gitRepo} into $ws")
 
-        val cloneProc = processes.builder(ctx.config, ctx.logFile, "")
+        val proc = processes.builder(ctx.config, ctx.logFile, "")
             .command("git", "clone", ctx.config.gitRepo, ".")
-            .directory(wsPath.toFile())
+            .directory(ws.toFile())
             .start()
-        handles.add(Handle(cloneProc.toHandle(), ctx.buildId))
+        handles.add(Handle(proc.toHandle(), ctx.buildId))
 
-        val cloneSuccess = cloneProc.waitFor(ctx.config.gitCloneTimeout, TimeUnit.SECONDS)
+        val cloneSuccess = proc.waitFor(ctx.config.gitCloneTimeout, TimeUnit.SECONDS)
         if (!cloneSuccess) {
             throw FailedToClone(ctx.buildId, ctx.config.gitRepo ?: "[no repo configured]")
         }
+    }
 
+    private fun checkout(ctx: BuildContext, ws: Workspace) {
         ctx.log("build ${ctx.buildId}: checkout rev ${ctx.rev}")
-        val checkoutProc = processes.builder(ctx.config, ctx.logFile, "")
+
+        val proc = processes.builder(ctx.config, ctx.logFile, "")
             .command("git", "checkout", ctx.rev)
-            .directory(wsPath.toFile())
+            .directory(ws.toFile())
             .start()
-        handles.add(Handle(checkoutProc.toHandle(), ctx.buildId))
+        handles.add(Handle(proc.toHandle(), ctx.buildId))
 
-        val checkoutSuccess = checkoutProc.waitFor(ctx.config.gitCloneTimeout, TimeUnit.SECONDS)
+        val checkoutSuccess = proc.waitFor(ctx.config.gitCloneTimeout, TimeUnit.SECONDS)
         if (!checkoutSuccess) {
             throw FailedToCheckout(ctx.buildId, ctx.config.gitRepo!!, ctx.rev)
         }
     }
 
-    private fun execScripts(ctx: BuildContext, wsPath: Path) {
-        val scriptFiles = listOf("pre.sh", "job.sh", "post.sh")
-
+    private fun execScripts(ctx: BuildContext, ws: Workspace) {
         ctx.log("build ${ctx.buildId}: looking for scripts $scriptFiles in $scriptsDir/")
 
         scriptFiles.forEach { script ->
-            val scriptFile = shFile(wsPath, script)
+            val scriptFile = shFile(ws, script)
             if (scriptFile.exists()) {
                 ctx.log("build ${ctx.buildId}: found script $script, running it")
 
@@ -95,7 +99,7 @@ class GitRunner(
 
                 val scriptProcess = processes.builder(ctx.config, ctx.logFile, ctx.rev)
                     .command(scriptFile.absolutePath)
-                    .directory(wsPath.toFile())
+                    .directory(ws.toFile())
                     .start()
                 handles.add(Handle(scriptProcess.toHandle(), ctx.buildId))
 
@@ -109,8 +113,8 @@ class GitRunner(
         }
     }
 
-    private fun shFile(wsPath: Path, name: String) =
-        wsPath.resolve(scriptsDir).resolve(name).toFile()
+    private fun shFile(ws: Workspace, name: String) =
+        ws.resolve(scriptsDir).resolve(name).toFile()
 
     val logger: Logger = LoggerFactory.getLogger(this::class.java)