moved the installing code to its own package

tests/installer/repo_installer_test.py

@@ -0,0 +1,52 @@
+import pytest
+import os
+
+import pre_commit.constants as C
+from plumbum import local
+from pre_commit.installer.repo_installer import create_repo_in_env
+from pre_commit.installer.repo_installer import install_pre_commit
+
+
+def get_sha(git_repo):
+    with local.cwd(git_repo):
+        return (local['git']['log', '--format="%H"'] | local['head']['-n1'])().strip('"\n')
+
+@pytest.mark.integration
+def test_create_repo_in_env(empty_git_dir, dummy_git_repo):
+    sha = get_sha(dummy_git_repo)
+    create_repo_in_env(dummy_git_repo, sha)
+
+    assert os.path.exists(os.path.join(dummy_git_repo, C.PRE_COMMIT_DIR, sha))
+
+@pytest.mark.integration
+def test_install_python_repo_in_env(empty_git_dir, python_pre_commit_git_repo):
+    sha = get_sha(python_pre_commit_git_repo)
+    install_pre_commit(python_pre_commit_git_repo,  sha)
+
+    assert os.path.exists(os.path.join(python_pre_commit_git_repo, C.PRE_COMMIT_DIR, sha, 'py_env'))
+
+
+@pytest.mark.integration
+def test_install_config(empty_git_dir, python_pre_commit_git_repo):
+
+    config = [
+        {
+            'repo': python_pre_commit_git_repo,
+            'sha': get_sha(python_pre_commit_git_repo),
+            'hooks': [
+                {
+                    'id': 'foo',
+                    'args': [
+                        {
+                            'type': 'files',
+                            'opt': '*.py'
+                        },
+                        ]
+                }
+            ],
+            },
+        ]
+    for repo in config:
+        install_pre_commit(repo['repo'], repo['sha'])
+
+    assert os.path.exists(os.path.join(python_pre_commit_git_repo, C.PRE_COMMIT_DIR, config[0]['sha'], 'py_env'))