4 files changed, 95 insertions, 4 deletions
diff --git a/tests/languages/docker_test.py b/tests/languages/docker_test.py
index 5838761..5f7c85e 100644
--- a/tests/languages/docker_test.py
+++ b/tests/languages/docker_test.py
@@ -178,6 +178,6 @@ def test_get_docker_path_in_docker_windows(in_docker):
 
 def test_get_docker_path_in_docker_docker_in_docker(in_docker):
     # won't be able to discover "self" container in true docker-in-docker
-    err = CalledProcessError(1, (), 0, b'', b'')
+    err = CalledProcessError(1, (), b'', b'')
     with mock.patch.object(docker, 'cmd_output_b', side_effect=err):
         assert docker._get_docker_path('/project') == '/project'
diff --git a/tests/languages/r_test.py b/tests/languages/r_test.py
index 5bc63b2..c52d5ac 100644
--- a/tests/languages/r_test.py
+++ b/tests/languages/r_test.py
@@ -6,6 +6,7 @@ import pytest
 
 from pre_commit import envcontext
 from pre_commit.languages import r
+from pre_commit.util import win_exe
 from testing.fixtures import make_config_from_repo
 from testing.fixtures import make_repo
 from tests.repository_test import _get_hook_no_install
@@ -133,7 +134,7 @@ def test_r_parsing_file_local(tempdir_factory, store):
 
 
 def test_rscript_exec_relative_to_r_home():
-    expected = os.path.join('r_home_dir', 'bin', 'Rscript')
+    expected = os.path.join('r_home_dir', 'bin', win_exe('Rscript'))
     with envcontext.envcontext((('R_HOME', 'r_home_dir'),)):
         assert r._rscript_exec() == expected
 
diff --git a/tests/languages/ruby_test.py b/tests/languages/ruby_test.py
index dc55456..29f3c80 100644
--- a/tests/languages/ruby_test.py
+++ b/tests/languages/ruby_test.py
@@ -71,10 +71,10 @@ def test_install_ruby_default(fake_gem_prefix):
 
 @xfailif_windows  # pragma: win32 no cover
 def test_install_ruby_with_version(fake_gem_prefix):
-    ruby.install_environment(fake_gem_prefix, '2.7.2', ())
+    ruby.install_environment(fake_gem_prefix, '3.1.0', ())
 
     # Should be able to activate and use rbenv install
-    with ruby.in_env(fake_gem_prefix, '2.7.2'):
+    with ruby.in_env(fake_gem_prefix, '3.1.0'):
         cmd_output('rbenv', 'install', '--help')
 
 
diff --git a/tests/languages/rust_test.py b/tests/languages/rust_test.py
new file mode 100644
index 0000000..f011e71
--- /dev/null
+++ b/tests/languages/rust_test.py
@@ -0,0 +1,90 @@
+from __future__ import annotations
+
+from unittest import mock
+
+import pytest
+
+import pre_commit.constants as C
+from pre_commit import parse_shebang
+from pre_commit.languages import rust
+from pre_commit.prefix import Prefix
+from pre_commit.util import cmd_output
+
+ACTUAL_GET_DEFAULT_VERSION = rust.get_default_version.__wrapped__
+
+
+@pytest.fixture
+def cmd_output_b_mck():
+    with mock.patch.object(rust, 'cmd_output_b') as mck:
+        yield mck
+
+
+def test_sets_system_when_rust_is_available(cmd_output_b_mck):
+    cmd_output_b_mck.return_value = (0, b'', b'')
+    assert ACTUAL_GET_DEFAULT_VERSION() == 'system'
+
+
+def test_uses_default_when_rust_is_not_available(cmd_output_b_mck):
+    cmd_output_b_mck.return_value = (127, b'', b'error: not found')
+    assert ACTUAL_GET_DEFAULT_VERSION() == C.DEFAULT
+
+
+@pytest.mark.parametrize('language_version', (C.DEFAULT, '1.56.0'))
+def test_installs_with_bootstrapped_rustup(tmpdir, language_version):
+    tmpdir.join('src', 'main.rs').ensure().write(
+        'fn main() {\n'
+        '    println!("Hello, world!");\n'
+        '}\n',
+    )
+    tmpdir.join('Cargo.toml').ensure().write(
+        '[package]\n'
+        'name = "hello_world"\n'
+        'version = "0.1.0"\n'
+        'edition = "2021"\n',
+    )
+    prefix = Prefix(str(tmpdir))
+
+    find_executable_exes = []
+
+    original_find_executable = parse_shebang.find_executable
+
+    def mocked_find_executable(exe: str) -> str | None:
+        """
+        Return `None` the first time `find_executable` is called to ensure
+        that the bootstrapping code is executed, then just let the function
+        work as normal.
+
+        Also log the arguments to ensure that everything works as expected.
+        """
+        find_executable_exes.append(exe)
+        if len(find_executable_exes) == 1:
+            return None
+        return original_find_executable(exe)
+
+    with mock.patch.object(parse_shebang, 'find_executable') as find_exe_mck:
+        find_exe_mck.side_effect = mocked_find_executable
+        rust.install_environment(prefix, language_version, ())
+        assert find_executable_exes == ['rustup', 'rustup', 'cargo']
+
+    with rust.in_env(prefix, language_version):
+        assert cmd_output('hello_world')[1] == 'Hello, world!\n'
+
+
+def test_installs_with_existing_rustup(tmpdir):
+    tmpdir.join('src', 'main.rs').ensure().write(
+        'fn main() {\n'
+        '    println!("Hello, world!");\n'
+        '}\n',
+    )
+    tmpdir.join('Cargo.toml').ensure().write(
+        '[package]\n'
+        'name = "hello_world"\n'
+        'version = "0.1.0"\n'
+        'edition = "2021"\n',
+    )
+    prefix = Prefix(str(tmpdir))
+
+    assert parse_shebang.find_executable('rustup') is not None
+    rust.install_environment(prefix, '1.56.0', ())
+    with rust.in_env(prefix, '1.56.0'):
+        assert cmd_output('hello_world')[1] == 'Hello, world!\n'