1 files changed, 133 insertions, 0 deletions
diff --git a/python/mach/mach/test/test_decorators.py b/python/mach/mach/test/test_decorators.py
new file mode 100644
index 0000000000..f33b6e7d8f
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+++ b/python/mach/mach/test/test_decorators.py
@@ -0,0 +1,133 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+from pathlib import Path
+from unittest import mock
+from unittest.mock import Mock, patch
+
+import pytest
+from mozbuild.base import MachCommandBase
+from mozunit import main
+
+import mach.decorators
+import mach.registrar
+from mach.base import MachError
+from mach.decorators import Command, CommandArgument, SubCommand
+from mach.requirements import MachEnvRequirements
+from mach.site import CommandSiteManager, MozSiteMetadata, SitePackagesSource
+
+
+@pytest.fixture
+def registrar(monkeypatch):
+    test_registrar = mach.registrar.MachRegistrar()
+    test_registrar.register_category(
+        "testing", "Mach unittest", "Testing for mach decorators"
+    )
+    monkeypatch.setattr(mach.decorators, "Registrar", test_registrar)
+    return test_registrar
+
+
+def test_register_command_with_argument(registrar):
+    inner_function = Mock()
+    context = Mock()
+    context.cwd = "."
+
+    @Command("cmd_foo", category="testing")
+    @CommandArgument("--arg", default=None, help="Argument help.")
+    def run_foo(command_context, arg):
+        inner_function(arg)
+
+    registrar.dispatch("cmd_foo", context, arg="argument")
+
+    inner_function.assert_called_with("argument")
+
+
+def test_register_command_with_metrics_path(registrar):
+    context = Mock()
+    context.cwd = "."
+
+    metrics_path = "metrics/path"
+    metrics_mock = Mock()
+    context.telemetry.metrics.return_value = metrics_mock
+
+    @Command("cmd_foo", category="testing", metrics_path=metrics_path)
+    def run_foo(command_context):
+        assert command_context.metrics == metrics_mock
+
+    @SubCommand("cmd_foo", "sub_foo", metrics_path=metrics_path + "2")
+    def run_subfoo(command_context):
+        assert command_context.metrics == metrics_mock
+
+    registrar.dispatch("cmd_foo", context)
+
+    context.telemetry.metrics.assert_called_with(metrics_path)
+    assert context.handler.metrics_path == metrics_path
+
+    registrar.dispatch("cmd_foo", context, subcommand="sub_foo")
+    assert context.handler.metrics_path == metrics_path + "2"
+
+
+def test_register_command_sets_up_class_at_runtime(registrar):
+    inner_function = Mock()
+
+    context = Mock()
+    context.cwd = "."
+
+    # We test that the virtualenv is set up properly dynamically on
+    # the instance that actually runs the command.
+    @Command("cmd_foo", category="testing", virtualenv_name="env_foo")
+    def run_foo(command_context):
+        assert (
+            Path(command_context.virtualenv_manager.virtualenv_root).name == "env_foo"
+        )
+        inner_function("foo")
+
+    @Command("cmd_bar", category="testing", virtualenv_name="env_bar")
+    def run_bar(command_context):
+        assert (
+            Path(command_context.virtualenv_manager.virtualenv_root).name == "env_bar"
+        )
+        inner_function("bar")
+
+    def from_environment_patch(
+        topsrcdir: str, state_dir: str, virtualenv_name, directory: str
+    ):
+        return CommandSiteManager(
+            "",
+            "",
+            virtualenv_name,
+            virtualenv_name,
+            MozSiteMetadata(0, "mach", SitePackagesSource.VENV, "", ""),
+            True,
+            MachEnvRequirements(),
+        )
+
+    with mock.patch.object(
+        CommandSiteManager, "from_environment", from_environment_patch
+    ):
+        with patch.object(MachCommandBase, "activate_virtualenv"):
+            registrar.dispatch("cmd_foo", context)
+            inner_function.assert_called_with("foo")
+            registrar.dispatch("cmd_bar", context)
+            inner_function.assert_called_with("bar")
+
+
+def test_cannot_create_command_nonexisting_category(registrar):
+    with pytest.raises(MachError):
+
+        @Command("cmd_foo", category="bar")
+        def run_foo(command_context):
+            pass
+
+
+def test_subcommand_requires_parent_to_exist(registrar):
+    with pytest.raises(MachError):
+
+        @SubCommand("sub_foo", "foo")
+        def run_foo(command_context):
+            pass
+
+
+if __name__ == "__main__":
+    main()