diff --git a/doc/build-helpers/testers.chapter.md b/doc/build-helpers/testers.chapter.md
index e4e8ddbb2c17..49407c6e9b8e 100644
--- a/doc/build-helpers/testers.chapter.md
+++ b/doc/build-helpers/testers.chapter.md
@@ -421,6 +421,11 @@ Check that two paths have the same contents.
 
 : A message that is printed last if the file system object contents at the two paths don't match exactly.
 
+`checkMetadata` (boolean)
+
+: Whether to fail on metadata differences, such as permissions or ownership.
+  Defaults to `true`.
+
 :::{.example #ex-testEqualContents-toyexample}
 
 # Check that two paths have the same contents
diff --git a/pkgs/build-support/testers/default.nix b/pkgs/build-support/testers/default.nix
index c35e03cada76..ac31c22ab4a2 100644
--- a/pkgs/build-support/testers/default.nix
+++ b/pkgs/build-support/testers/default.nix
@@ -57,6 +57,7 @@
       actual,
       expected,
       postFailureMessage ? null,
+      checkMetadata ? true,
     }:
     runCommand "equal-contents-${lib.strings.toLower assertion}"
       {
@@ -66,12 +67,13 @@
           expected
           postFailureMessage
           ;
+        excludeMetadata = if checkMetadata then "no" else "yes";
         nativeBuildInputs = [ diffoscopeMinimal ];
       }
       ''
         echo "Checking:"
         printf '%s\n' "$assertion"
-        if ! diffoscope --no-progress --text-color=always --exclude-directory-metadata=no -- "$actual" "$expected"
+        if ! diffoscope --no-progress --text-color=always --exclude-directory-metadata="$excludeMetadata" -- "$actual" "$expected"
         then
           echo
           echo 'Contents must be equal, but were not!'
diff --git a/pkgs/development/python-modules/keymap-drawer/default.nix b/pkgs/development/python-modules/keymap-drawer/default.nix
index fb6083a90802..fffc10aa8252 100644
--- a/pkgs/development/python-modules/keymap-drawer/default.nix
+++ b/pkgs/development/python-modules/keymap-drawer/default.nix
@@ -2,9 +2,11 @@
   lib,
 
   buildPythonPackage,
+  callPackages,
   fetchFromGitHub,
   pythonOlder,
 
+  keymap-drawer,
   nix-update-script,
   pcpp,
   platformdirs,
@@ -59,6 +61,12 @@ buildPythonPackage {
   versionCheckProgram = "${placeholder "out"}/bin/keymap";
   versionCheckProgramArg = "--version";
 
+  passthru.tests = callPackages ./tests {
+    # Explicitly pass the correctly scoped package.
+    # The top-level package will still resolve to itself, because the way
+    # `toPythonApplication` interacts with scopes is weird.
+    inherit keymap-drawer;
+  };
   passthru.updateScript = nix-update-script { };
 
   meta = {
diff --git a/pkgs/development/python-modules/keymap-drawer/tests/default.nix b/pkgs/development/python-modules/keymap-drawer/tests/default.nix
new file mode 100644
index 000000000000..7c94185c41f5
--- /dev/null
+++ b/pkgs/development/python-modules/keymap-drawer/tests/default.nix
@@ -0,0 +1,89 @@
+{
+  lib,
+  fetchFromGitHub,
+  runCommand,
+  stdenv,
+  testers,
+
+  keymap-drawer,
+  yamllint,
+}:
+let
+  runKeymapDrawer =
+    name:
+    runCommand "keymap-drawer-${name}" {
+      nativeBuildInputs = [ keymap-drawer ];
+    };
+
+  MattSturgeon-example = fetchFromGitHub {
+    owner = "MattSturgeon";
+    repo = "glove80-config";
+    rev = "d55267dd26593037256b35a5d6ebba0f75541da5";
+    hash = "sha256-MV6cNpgHBuaGvpu2aR1aBNMpwPnDqOSbGf+2ykxocP4=";
+    nonConeMode = true;
+    sparseCheckout = [
+      "config"
+      "img"
+    ];
+  };
+
+  # MattSturgeon's example requires MDI icons
+  mdi = fetchFromGitHub {
+    owner = "Templarian";
+    repo = "MaterialDesign-SVG";
+    tag = "v7.4.47";
+    hash = "sha256-NoSSRT1ID38MT70IZ+7h/gMVCNsjNs3A2RX6ePGwuQ0=";
+  };
+in
+{
+  dump-config = runKeymapDrawer "dump-config" ''
+    keymap dump-config --output "$out"
+
+    if [ ! -s "$out" ]; then
+      >&2 echo 'Expected `dump-config` to have content.'
+      exit 1
+    fi
+
+    ${lib.getExe yamllint} --strict --config-data relaxed "$out"
+  '';
+
+  parse-zmk = testers.testEqualContents {
+    assertion = "keymap parse --zmk-keymap produces expected YAML";
+    expected = "${MattSturgeon-example}/img/glove80.yaml";
+    actual = runKeymapDrawer "parse" ''
+      keymap \
+        --config ${MattSturgeon-example}/config/keymap_drawer.yaml \
+        parse --zmk-keymap ${MattSturgeon-example}/config/glove80.keymap \
+        --output "$out"
+    '';
+    checkMetadata = stdenv.buildPlatform.isLinux;
+  };
+
+  draw = testers.testEqualContents {
+    assertion = "keymap draw produces expected SVG";
+    expected = "${MattSturgeon-example}/img/glove80.svg";
+    actual = runKeymapDrawer "draw" ''
+      ${lib.optionalString stdenv.buildPlatform.isLinux ''
+        export XDG_CACHE_HOME="$PWD/cache"
+        glyphs="$XDG_CACHE_HOME/keymap-drawer/glyphs"
+      ''}
+      ${lib.optionalString stdenv.buildPlatform.isDarwin ''
+        export HOME="$PWD/home"
+        glyphs="$HOME/Library/Caches/keymap-drawer/glyphs"
+      ''}
+      mkdir -p "$glyphs"
+
+      # Unpack MDI icons into the cache
+      for file in ${mdi}/svg/*
+      do
+        ln -s "$file" "$glyphs/mdi:$(basename "$file")"
+      done
+
+      keymap \
+        --config ${MattSturgeon-example}/config/keymap_drawer.yaml \
+        draw ${MattSturgeon-example}/img/glove80.yaml \
+        --output "$out"
+    '';
+    checkMetadata = stdenv.buildPlatform.isLinux;
+  };
+}