diff --git a/flake.lock b/flake.lock
index f1a0875..598eafa 100644
--- a/flake.lock
+++ b/flake.lock
@@ -329,6 +329,23 @@
         "type": "github"
       }
     },
+    "nixtest": {
+      "locked": {
+        "dir": "lib",
+        "lastModified": 1746388457,
+        "narHash": "sha256-xWAnSFxogdy47rZyGj18R9qDlLFs/PvwPpD3iAiR2Hc=",
+        "owner": "technofab",
+        "repo": "nixtest",
+        "rev": "0a1bbae2c30e3ba8e3b02de223e199c5dfd56572",
+        "type": "gitlab"
+      },
+      "original": {
+        "dir": "lib",
+        "owner": "technofab",
+        "repo": "nixtest",
+        "type": "gitlab"
+      }
+    },
     "root": {
       "inputs": {
         "devenv": "devenv",
@@ -336,6 +353,7 @@
         "mkdocs-material-umami": "mkdocs-material-umami",
         "nix-mkdocs": "nix-mkdocs",
         "nixpkgs": "nixpkgs_4",
+        "nixtest": "nixtest",
         "systems": "systems",
         "treefmt-nix": "treefmt-nix"
       }
diff --git a/flake.nix b/flake.nix
index 6753d41..2704302 100644
--- a/flake.nix
+++ b/flake.nix
@@ -9,6 +9,7 @@
         inputs.devenv.flakeModule
         inputs.treefmt-nix.flakeModule
         inputs.nix-mkdocs.flakeModule
+        inputs.nixtest.flakeModule
         ./lib/flakeModule.nix
       ];
       systems = import systems;
@@ -16,6 +17,7 @@
       perSystem = {
         pkgs,
         config,
+        self',
         system,
         ...
       }: rec {
@@ -209,6 +211,23 @@
           };
         };
 
+        nixtest.suites = let
+          jsonFile = file: builtins.fromJSON (builtins.readFile file);
+        in {
+          "Pipeline YAMLs" = [
+            {
+              name = "default";
+              type = "snapshot";
+              actual = jsonFile self'.legacyPackages."gitlab-ci:pipeline:default";
+            }
+            {
+              name = "non-default";
+              type = "snapshot";
+              actual = jsonFile self'.legacyPackages."gitlab-ci:pipeline:non-default";
+            }
+          ];
+        };
+
         packages = let
           setupScript = pkgs.writeShellScriptBin "setup_nix_ci" (builtins.readFile ./scripts/setup_nix_ci.sh);
           finalizeScript = pkgs.writeShellScriptBin "finalize_nix_ci" (builtins.readFile ./scripts/finalize_nix_ci.sh);
@@ -269,6 +288,7 @@
     treefmt-nix.url = "github:numtide/treefmt-nix";
     nix-mkdocs.url = "gitlab:technofab/nixmkdocs?dir=lib";
     mkdocs-material-umami.url = "gitlab:technofab/mkdocs-material-umami";
+    nixtest.url = "gitlab:technofab/nixtest?dir=lib";
   };
 
   nixConfig = {
diff --git a/snapshots/default.snap.json b/snapshots/default.snap.json
new file mode 100644
index 0000000..48ae054
--- /dev/null
+++ b/snapshots/default.snap.json
@@ -0,0 +1 @@
+{"docs":{"after_script":["finalize_nix_ci"],"artifacts":{"paths":["public"]},"before_script":["source setup_nix_ci \"gitlab-ci:pipeline:default:job-deps:docs\""],"cache":[],"image":"$NIX_CI_IMAGE","script":["nix build .#docs:default\nmkdir -p public\ncp -r result/. public/\n"],"stage":"build","variables":{}},"pages":{"artifacts":{"paths":["public"]},"image":"alpine:latest","rules":[{"if":"$CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH"}],"script":["true"],"stage":"deploy"},"stages":["test","build","deploy"],"test":{"after_script":["finalize_nix_ci"],"before_script":["source setup_nix_ci \"gitlab-ci:pipeline:default:job-deps:test\""],"cache":[{"key":"$CI_JOB_NAME-$CI_COMMIT_REF_SLUG","paths":[".nix-cache/"]}],"image":"$NIX_CI_IMAGE","script":["hello","curl google.de","echo $TEST $TEST_WITH_DERIVATION"],"stage":"test","variables":{"NIX_CI_CACHE_STRATEGY":"runner","TEST":"test"}},"test-default":{"after_script":["finalize_nix_ci"],"before_script":["source setup_nix_ci \"gitlab-ci:pipeline:default:job-deps:test-default\""],"cache":[],"image":"$NIX_CI_IMAGE","script":["hello"],"stage":"test","variables":{}},"test-non-nix":{"image":"alpine:latest","script":["echo \"This job will not be modified to use nix\""],"stage":"test"}}
\ No newline at end of file
diff --git a/snapshots/non-default.snap.json b/snapshots/non-default.snap.json
new file mode 100644
index 0000000..6a613ef
--- /dev/null
+++ b/snapshots/non-default.snap.json
@@ -0,0 +1 @@
+{"stages":["test"],"test":{"after_script":["finalize_nix_ci"],"before_script":["source setup_nix_ci \"gitlab-ci:pipeline:non-default:job-deps:test\""],"cache":[],"image":"$NIX_CI_IMAGE","script":["echo Hello from another pipeline"],"stage":"test","variables":{}}}
\ No newline at end of file