diff --git a/tests/modules/programs/diff-highlight/default.nix b/tests/modules/programs/diff-highlight/default.nix
index 5bdbe52dd..8764b8c56 100644
--- a/tests/modules/programs/diff-highlight/default.nix
+++ b/tests/modules/programs/diff-highlight/default.nix
@@ -2,4 +2,5 @@
   diff-highlight-basic = ./diff-highlight-basic.nix;
   diff-highlight-with-git-integration = ./diff-highlight-with-git-integration.nix;
   diff-highlight-migration = ./diff-highlight-migration.nix;
+  diff-highlight-git-package-null-assertion = ./diff-highlight-git-package-null-assertion.nix;
 }
diff --git a/tests/modules/programs/diff-highlight/diff-highlight-git-package-null-assertion.nix b/tests/modules/programs/diff-highlight/diff-highlight-git-package-null-assertion.nix
new file mode 100644
index 000000000..52e795bc6
--- /dev/null
+++ b/tests/modules/programs/diff-highlight/diff-highlight-git-package-null-assertion.nix
@@ -0,0 +1,18 @@
+{
+  programs.diff-highlight = {
+    enable = true;
+    enableGitIntegration = true;
+  };
+
+  programs.git = {
+    enable = true;
+    package = null;
+  };
+
+  test.asserts.assertions.expected = [
+    ''
+      programs.diff-highlight.enableGitIntegration requires programs.git.package to be set.
+      Please set programs.git.package to a valid git package.
+    ''
+  ];
+}