diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 9d5a1f0..83aa787 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -32,3 +32,17 @@ jobs:
 
       - name: Check diff
         run: git diff
+
+  not_semver:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: ./
+        id: depup
+        with:
+          file: testdata/testfile
+          version_name: TMUX_VERSION
+          repo: tmux/tmux
+
+      - name: Check diff
+        run: git diff
diff --git a/testdata/testfile b/testdata/testfile
index 33f8ca0..eb921a6 100644
--- a/testdata/testfile
+++ b/testdata/testfile
@@ -14,3 +14,5 @@ The above version should be updated to the latest version with this action.
 Other test cases.
 
 REDPEN_VERSION=1.10.1
+
+TMUX_VERSION=3.0