tests: merge both flakes

we used to have a flake in tests/flake.nix on top of the top-level one.
This results in 2 lockfiles for the same purpose and is not practical.
Instead this moves tests to legacyPackages:

- so they dont appear in "nix flake show" as it can be inconvenient
- legacyPackages supported nested attribute sets of derivations which
  could let us regroup tests under a same set and build that instead.
  For instance, one could `nix build .#tests.neovim` and build all of
  neovim packages. One could still pick a single `nix build
  .#tests.neovim.plugin-config`

dont expose tests into devShells to limit

fix python test runner to find the tests where appropriate

flake.nix

@@ -48,6 +48,113 @@
         forAllPkgs =
           f:
           nixpkgs.lib.genAttrs nixpkgs.lib.systems.flakeExposed (system: f nixpkgs.legacyPackages.${system});
+
+        forCI = nixpkgs.lib.genAttrs [
+          "aarch64-darwin"
+          "x86_64-linux"
+        ];
+
+        testChunks =
+          system:
+          let
+            pkgs = nixpkgs.legacyPackages.${system};
+            inherit (pkgs) lib;
+
+            # Create chunked test packages for better CI parallelization
+            tests = import ./tests {
+              inherit pkgs;
+              # Disable big tests since this is only used for CI
+              enableBig = false;
+            };
+            allTests = lib.attrNames tests.build;
+            # Remove 'all' from the test list as it's a meta-package
+            filteredTests = lib.filter (name: name != "all") allTests;
+            # NOTE: Just a starting value, we can tweak this to find a good value.
+            targetTestsPerChunk = 50;
+            numChunks = lib.max 1 (
+              builtins.ceil ((builtins.length filteredTests) / (targetTestsPerChunk * 1.0))
+            );
+            chunkSize = builtins.ceil ((builtins.length filteredTests) / (numChunks * 1.0));
+
+            makeChunk =
+              chunkNum: testList:
+              let
+                start = (chunkNum - 1) * chunkSize;
+                end = lib.min (start + chunkSize) (builtins.length testList);
+                chunkTests = lib.sublist start (end - start) testList;
+                chunkAttrs = lib.genAttrs chunkTests (name: tests.build.${name});
+              in
+              pkgs.symlinkJoin {
+                name = "test-chunk-${toString chunkNum}";
+                paths = lib.attrValues chunkAttrs;
+                passthru.tests = chunkTests;
+              };
+          in
+          lib.listToAttrs (
+            lib.genList (
+              i: lib.nameValuePair "test-chunk-${toString (i + 1)}" (makeChunk (i + 1) filteredTests)
+            ) numChunks
+          );
+
+        integrationTests =
+          system:
+          let
+            pkgs = nixpkgs.legacyPackages.${system};
+            inherit (pkgs) lib;
+          in
+          lib.optionalAttrs pkgs.stdenv.hostPlatform.isLinux (
+            let
+              tests = import ./tests/integration { inherit pkgs lib; };
+              renameTestPkg = n: v: lib.nameValuePair "integration-${n}" v;
+            in
+            lib.mapAttrs' renameTestPkg (lib.removeAttrs tests [ "all" ])
+          );
+
+        buildTests =
+          system:
+          let
+            pkgs = nixpkgs.legacyPackages.${system};
+            tests = import ./tests { inherit pkgs; };
+            renameTestPkg = n: nixpkgs.lib.nameValuePair "test-${n}";
+          in
+          nixpkgs.lib.mapAttrs' renameTestPkg tests.build;
+
+        buildTestsNoBig =
+          system:
+          let
+            pkgs = nixpkgs.legacyPackages.${system};
+            tests = import ./tests {
+              inherit pkgs;
+              enableBig = false;
+            };
+          in
+          {
+            test-all-enableBig-false-enableLegacyIfd-false = tests.build.all;
+          };
+
+        buildTestsNoBigIfd =
+          system:
+          let
+            pkgs = nixpkgs.legacyPackages.${system};
+            tests = import ./tests {
+              inherit pkgs;
+              enableBig = false;
+              enableLegacyIfd = true;
+            };
+          in
+          {
+            test-all-enableBig-false-enableLegacyIfd-true = tests.build.all;
+          };
+
+        integrationTestPackages =
+          system:
+          let
+            pkgs = nixpkgs.legacyPackages.${system};
+            inherit (pkgs) lib;
+            tests = import ./tests/integration { inherit pkgs lib; };
+            renameTestPkg = n: lib.nameValuePair "integration-test-${n}";
+          in
+          lib.mapAttrs' renameTestPkg tests;
       in
       {
         formatter = forAllPkgs (
@@ -63,6 +170,22 @@
           }
         );
 
+        # TODO: increase buildbot testing scope
+        buildbot = forCI (
+          system:
+          let
+            allIntegrationTests = integrationTests system;
+            workingIntegrationTests = nixpkgs.lib.filterAttrs (
+              name: _:
+              nixpkgs.lib.elem name [
+                "integration-nixos-basics"
+                "integration-nixos-legacy-profile-management"
+              ]
+            ) allIntegrationTests;
+          in
+          (testChunks system) // workingIntegrationTests
+        );
+
         packages = forAllPkgs (
           pkgs:
           let
@@ -90,6 +213,19 @@
             docs-manpages = docs.manPages;
           }
         );
+
+        legacyPackages = forAllPkgs (
+          pkgs:
+          let
+            system = pkgs.stdenv.hostPlatform.system;
+          in
+          (buildTests system)
+          // (integrationTestPackages system)
+          // (buildTestsNoBig system)
+          // (buildTestsNoBigIfd system)
+          // (testChunks system)
+          // (integrationTests system)
+        );
       }
     );
 }

tests/flake.nix

@@ -1,169 +0,0 @@
-# This is an internal Nix Flake intended for use when running tests.
-#
-# You can build all tests or specific tests by running
-#
-#   nix build --reference-lock-file flake.lock ./tests#test-all
-#   nix build --reference-lock-file flake.lock ./tests#test-alacritty-empty-settings
-#
-# in the Home Manager project root directory.
-#
-# Similarly for integration tests
-#
-#   nix build --reference-lock-file flake.lock ./tests#integration-test-all
-#   nix build --reference-lock-file flake.lock ./tests#integration-test-standalone-standard-basics
-
-{
-  description = "Tests of Home Manager for Nix";
-
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-
-  outputs =
-    { nixpkgs, ... }:
-    let
-      forAllSystems = nixpkgs.lib.genAttrs nixpkgs.lib.systems.flakeExposed;
-      forCI = nixpkgs.lib.genAttrs [
-        "aarch64-darwin"
-        "x86_64-linux"
-      ];
-
-      testChunks =
-        system:
-        let
-          pkgs = nixpkgs.legacyPackages.${system};
-          inherit (pkgs) lib;
-
-          # Create chunked test packages for better CI parallelization
-          tests = import ./. {
-            inherit pkgs;
-            # Disable big tests since this is only used for CI
-            enableBig = false;
-          };
-          allTests = lib.attrNames tests.build;
-          # Remove 'all' from the test list as it's a meta-package
-          filteredTests = lib.filter (name: name != "all") allTests;
-          # NOTE: Just a starting value, we can tweak this to find a good value.
-          targetTestsPerChunk = 50;
-          numChunks = lib.max 1 (
-            builtins.ceil ((builtins.length filteredTests) / (targetTestsPerChunk * 1.0))
-          );
-          chunkSize = builtins.ceil ((builtins.length filteredTests) / (numChunks * 1.0));
-
-          makeChunk =
-            chunkNum: testList:
-            let
-              start = (chunkNum - 1) * chunkSize;
-              end = lib.min (start + chunkSize) (builtins.length testList);
-              chunkTests = lib.sublist start (end - start) testList;
-              chunkAttrs = lib.genAttrs chunkTests (name: tests.build.${name});
-            in
-            pkgs.symlinkJoin {
-              name = "test-chunk-${toString chunkNum}";
-              paths = lib.attrValues chunkAttrs;
-              passthru.tests = chunkTests;
-            };
-        in
-        lib.listToAttrs (
-          lib.genList (
-            i: lib.nameValuePair "test-chunk-${toString (i + 1)}" (makeChunk (i + 1) filteredTests)
-          ) numChunks
-        );
-
-      integrationTests =
-        system:
-        let
-          pkgs = nixpkgs.legacyPackages.${system};
-          inherit (pkgs) lib;
-        in
-        lib.optionalAttrs pkgs.stdenv.hostPlatform.isLinux (
-          let
-            tests = import ./integration { inherit pkgs lib; };
-            renameTestPkg = n: v: lib.nameValuePair "integration-${n}" v;
-          in
-          lib.mapAttrs' renameTestPkg (lib.removeAttrs tests [ "all" ])
-        );
-
-      # Test group definitions
-      buildTests =
-        system:
-        let
-          pkgs = nixpkgs.legacyPackages.${system};
-          tests = import ./. { inherit pkgs; };
-          renameTestPkg = n: nixpkgs.lib.nameValuePair "test-${n}";
-        in
-        nixpkgs.lib.mapAttrs' renameTestPkg tests.build;
-
-      buildTestsNoBig =
-        system:
-        let
-          pkgs = nixpkgs.legacyPackages.${system};
-          tests = import ./. {
-            inherit pkgs;
-            enableBig = false;
-          };
-        in
-        {
-          test-all-enableBig-false-enableLegacyIfd-false = tests.build.all;
-        };
-
-      buildTestsNoBigIfd =
-        system:
-        let
-          pkgs = nixpkgs.legacyPackages.${system};
-          tests = import ./. {
-            inherit pkgs;
-            enableBig = false;
-            enableLegacyIfd = true;
-          };
-        in
-        {
-          test-all-enableBig-false-enableLegacyIfd-true = tests.build.all;
-        };
-
-      integrationTestPackages =
-        system:
-        let
-          pkgs = nixpkgs.legacyPackages.${system};
-          inherit (pkgs) lib;
-          tests = import ./integration { inherit pkgs lib; };
-          renameTestPkg = n: lib.nameValuePair "integration-test-${n}";
-        in
-        lib.mapAttrs' renameTestPkg tests;
-
-    in
-    {
-      # TODO: increase buildbot testing scope
-      buildbot = forCI (
-        system:
-        let
-          allIntegrationTests = integrationTests system;
-          workingIntegrationTests = nixpkgs.lib.filterAttrs (
-            name: _:
-            nixpkgs.lib.elem name [
-              "integration-nixos-basics"
-              "integration-nixos-legacy-profile-management"
-            ]
-          ) allIntegrationTests;
-        in
-        (testChunks system) // workingIntegrationTests
-      );
-
-      devShells = forAllSystems (
-        system:
-        let
-          pkgs = nixpkgs.legacyPackages.${system};
-          tests = import ./. { inherit pkgs; };
-        in
-        tests.run
-      );
-
-      packages = forAllSystems (
-        system:
-        (buildTests system)
-        // (integrationTestPackages system)
-        // (buildTestsNoBig system)
-        // (buildTestsNoBigIfd system)
-        // (testChunks system)
-        // (integrationTests system)
-      );
-    };
-}

tests/tests.py

@@ -64,8 +64,7 @@ class TestRunner:
         )
 
         cmd = [
-            "nix", "eval", "--raw", "--reference-lock-file", "flake.lock",
-            f"./tests#packages.{system}", "--apply", nix_apply_expr
+            "nix", "eval", "--raw", f".#legacyPackages.{system}", "--apply", nix_apply_expr
         ]
 
         result = _run_command(cmd, cwd=self.repo_root)