diff --git a/src/main/kotlin/de/smartsquare/squit/config/ConfigExtensions.kt b/src/main/kotlin/de/smartsquare/squit/config/ConfigExtensions.kt
index 9ae243f..ee916f4 100644
--- a/src/main/kotlin/de/smartsquare/squit/config/ConfigExtensions.kt
+++ b/src/main/kotlin/de/smartsquare/squit/config/ConfigExtensions.kt
@@ -50,7 +50,7 @@ val Config.title: String get() = getSafeString(TITLE)
 /**
  * The path to the directory of the test
  */
-val Config.testDir: Path get() = Paths.get(getSafeString(TEST_DIRECTORY))
+val Config.testDir: Path get() = FilesUtils.validateExistence(Paths.get(getSafeString(TEST_DIRECTORY)))
 
 /**
  * The endpoint to request against.
@@ -175,7 +175,7 @@ fun Config.withTestDir(testDir: Path): Config = withValue(
  */
 fun Config.validate() = this.apply {
     // Call getters of properties to check existence and correct declaration.
-    endpoint; mediaType; shouldExclude; shouldIgnore; headers
+    endpoint; mediaType; shouldExclude; shouldIgnore; headers; testDir
 
     preProcessors.forEach { checkClass(it) }
     preProcessorScripts.forEach { FilesUtils.validateExistence(it) }
diff --git a/src/test/kotlin/de/smartsquare/squit/config/ConfigExtensionsTest.kt b/src/test/kotlin/de/smartsquare/squit/config/ConfigExtensionsTest.kt
index b2e7d0a..6c58942 100644
--- a/src/test/kotlin/de/smartsquare/squit/config/ConfigExtensionsTest.kt
+++ b/src/test/kotlin/de/smartsquare/squit/config/ConfigExtensionsTest.kt
@@ -12,6 +12,7 @@ import org.amshove.kluent.shouldThrow
 import org.amshove.kluent.withMessage
 import org.gradle.api.GradleException
 import org.junit.jupiter.api.Test
+import java.nio.file.Paths
 
 class ConfigExtensionsTest {
 
@@ -82,6 +83,34 @@ class ConfigExtensionsTest {
         config.method shouldBeEqualTo "POST"
     }
 
+    @Test
+    fun `config object with a valid testDir`() {
+        val config = ConfigFactory.parseMap(
+            mapOf(
+                "endpoint" to "https://example.com",
+                "testDir" to Paths.get(".").toString()
+            )
+        )
+
+        val call = { config.validate() }
+
+        call shouldNotThrow AnyException
+    }
+
+    @Test
+    fun `config object with an invalid testDir`() {
+        val config = ConfigFactory.parseMap(
+            mapOf(
+                "endpoint" to "https://example.com",
+                "testDir" to Paths.get("does_not_exist").toString()
+            )
+        )
+
+        val call = { config.validate() }
+
+        call shouldThrow GradleException::class withMessage "Missing expected file: does_not_exist"
+    }
+
     @Test
     fun `config object with a valid preProcessor`() {
         val config = ConfigFactory.parseMap(