feat: add module options tests

tests/flake-module.nix

@@ -31,6 +31,10 @@
           modules = [ ../examples/minimal/arion-compose.nix ];
         };
 
+        testModuleOptions = import ./module-options-arion-test {
+          inherit lib;
+          pkgs = final;
+        };
       };
     };
 }

tests/module-options-arion-test/default.nix

@@ -0,0 +1,76 @@
+{ pkgs, lib ? pkgs.lib, ... }:
+let
+  inherit (lib) any escapeShellArg replaceStrings runTests toList;
+
+  evalComposition = modules: import ../../src/nix/eval-composition.nix {
+    inherit pkgs;
+    modules = toList modules;
+  };
+
+  testComposition = { expected, fn, config }: {
+    inherit expected;
+    expr = fn (evalComposition config);
+  };
+
+  search = pattern: str: (builtins.match ".*${pattern}.*" str) != null;
+
+  assertionsMatch = patterns: assertions:
+    let
+      failed = builtins.filter (assertion: !assertion.assertion) assertions;
+      matchAnyPattern = assertion: any (pattern: search pattern assertion.message) (toList patterns);
+    in
+    any matchAnyPattern failed;
+
+  checkAssertions = expected: patterns: config: testComposition {
+    inherit expected config;
+    fn = composition: assertionsMatch patterns composition.config.assertions;
+  };
+
+  checkAssertionsMatch = checkAssertions true;
+  checkAssertionsDoNotMatch = checkAssertions false;
+
+  mkRepoTagAssertionPattern = component: attrName: name: replaceStrings [ "\n" ] [ " " ] ''
+    Unable to infer the ${component} of the image associated with
+    config\.services\.${name}\.  Please set
+    config\.services\.${name}\.image\.${attrName} to a non-empty string\.
+  '';
+
+  imageNameAssertionPattern = mkRepoTagAssertionPattern "name" "imageName";
+  imageTagAssertionPattern = mkRepoTagAssertionPattern "tag" "imageTag";
+
+  tests = runTests {
+    testNoImageName = checkAssertionsMatch (imageNameAssertionPattern "no-name") {
+      services.no-name.image = {
+        tarball = "/no/name.tar.gz";
+        tag = "test";
+      };
+    };
+
+    testNoImageTag = checkAssertionsMatch (imageTagAssertionPattern "no-tag") {
+      services.no-tag.image = {
+        tarball = "/no/tag.tar.gz";
+        name = "test";
+      };
+    };
+
+    testImageNameInference = testComposition {
+      config = {
+        services.nix-store-path.image.tarball = builtins.storeDir + "/foo-bar-baz.tar.gz";
+      };
+      expected = "bar-baz";
+      fn = composition: composition.config.services.nix-store-path.image.tarball.imageName;
+    };
+
+    testImageTagInference = testComposition {
+      config = {
+        services.nix-store-path.image.tarball = builtins.storeDir + "/foo-bar-baz.tar.gz";
+      };
+      expected = "foo";
+      fn = composition: composition.config.services.nix-store-path.image.tarball.imageTag;
+    };
+  };
+in
+# Abort if `tests`(list containing failed tests) is not empty
+pkgs.runCommandNoCC "module-options-arion-test" { } ''
+  ${pkgs.jq}/bin/jq 'if . == [] then . else halt_error(1) end' > "$out" <<<${escapeShellArg (builtins.toJSON tests)}
+''