diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 1025948..9d27494 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -221,6 +221,13 @@ integration-test-oni-conf:
     - package
   script: make integration-test-oni-conf TEST_ARCHIVE=$(realpath bin/)
 
+integration-test-oni-csharp:
+  stage: integration-test
+  image: registry.gitlab.com/ryuslash/emacs-config
+  dependencies:
+    - package
+  script: make integration-test-oni-csharp TEST_ARCHIVE=$(realpath bin/)
+
 integration-test-oni-bookmark:
   stage: integration-test
   image: registry.gitlab.com/ryuslash/emacs-config
diff --git a/test/integration/oni-csharp.bats b/test/integration/oni-csharp.bats
new file mode 100644
index 0000000..241a335
--- /dev/null
+++ b/test/integration/oni-csharp.bats
@@ -0,0 +1,21 @@
+#!/usr/bin/env bats
+
+@test "Opening a .cs file loads oni-csharp" {
+    run emacs -batch -l package -f package-initialize \
+        -visit test.cs \
+        -eval "(prin1 (featurep 'oni-csharp))"
+
+    echo "$output"
+
+    [[ "$output" == *"t" ]]
+}
+
+@test "Opening a .xaml file loads nxml-mode" {
+    run emacs -batch -l package -f package-initialize \
+        -visit test.xaml \
+        -eval "(prin1 major-mode)"
+
+    echo "$output"
+
+    [[ "$output" == *"nxml-mode" ]]
+}