Create an upgrade command

This command will assist users with migration from 1.x.x to 2.0.0.

test/conftest.py

@@ -84,6 +84,7 @@ def supported_commands():
         'introspect',
         'list',
         'perms',
+        'upgrade',
         'version',
         ]
 

test/test_unit_issue_legacy_path_warning.py

@@ -10,25 +10,30 @@ import pytest
         'encrypt',
         'files.gpg',
         'bootstrap',
-        'hooks',
+        'hooks/pre_command',
+        'hooks/post_command',
         ],
     )
-def test_legacy_warning(tmpdir, runner, yadm, legacy_path):
+@pytest.mark.parametrize(
+    'upgrade', [True, False], ids=['upgrade', 'no-upgrade'])
+def test_legacy_warning(tmpdir, runner, yadm, upgrade, legacy_path):
     """Use issue_legacy_path_warning"""
     home = tmpdir.mkdir('home')
 
     if legacy_path:
-        home.mkdir(f'.yadm').mkdir(legacy_path)
+        home.mkdir(f'.yadm').ensure(legacy_path)
 
+    main_args = 'MAIN_ARGS=("upgrade")' if upgrade else ''
     script = f"""
         HOME={home}
         YADM_TEST=1 source {yadm}
+        {main_args}
         issue_legacy_path_warning
     """
     run = runner(command=['bash'], inp=script)
     assert run.success
     assert run.err == ''
-    if legacy_path:
+    if legacy_path and not upgrade:
         assert 'Legacy configuration paths have been detected' in run.out
     else:
         assert run.out.rstrip() == ''

test/test_unit_upgrade.py

@@ -0,0 +1,101 @@
+"""Unit tests: upgrade"""
+import pytest
+
+LEGACY_PATHS = [
+    'config',
+    'encrypt',
+    'files.gpg',
+    'bootstrap',
+    'hooks/pre_command',
+    'hooks/post_command',
+]
+
+# used:
+# YADM_COMPATIBILITY
+# YADM_DIR
+# YADM_LEGACY_DIR
+# GIT_PROGRAM
+@pytest.mark.parametrize('condition', ['compat', 'equal', 'existing_repo'])
+def test_upgrade_errors(tmpdir, runner, yadm, condition):
+    """Test upgrade() error conditions"""
+
+    compatibility = 'YADM_COMPATIBILITY=1' if condition == 'compat' else ''
+
+    home = tmpdir.mkdir('home')
+    yadm_dir = home.join('.config/yadm')
+    legacy_dir = home.join('.yadm')
+    if condition == 'equal':
+        legacy_dir = yadm_dir
+    if condition == 'existing_repo':
+        yadm_dir.ensure_dir('repo.git')
+        legacy_dir.ensure_dir('repo.git')
+
+    script = f"""
+        YADM_TEST=1 source {yadm}
+        {compatibility}
+        YADM_DIR="{yadm_dir}"
+        YADM_REPO="{yadm_dir}/repo.git"
+        YADM_LEGACY_DIR="{legacy_dir}"
+        upgrade
+    """
+    run = runner(command=['bash'], inp=script)
+    assert run.failure
+    assert run.err == ''
+    assert 'Unable to upgrade' in run.out
+    if condition == 'compat':
+        assert 'YADM_COMPATIBILITY' in run.out
+    if condition == 'equal':
+        assert 'has been resolved as' in run.out
+    if condition == 'existing_repo':
+        assert 'already exists' in run.out
+
+
+@pytest.mark.parametrize('condition', ['no-paths', 'untracked', 'tracked'])
+def test_upgrade(tmpdir, runner, yadm, condition):
+    """Test upgrade()
+
+    When testing the condition of git-tracked data, "echo" will be used as a
+    mock for git. echo will return true, simulating a positive result from "git
+    ls-files". Also echo will report the parameters for "git mv".
+    """
+    home = tmpdir.mkdir('home')
+    yadm_dir = home.join('.config/yadm')
+    legacy_dir = home.join('.yadm')
+
+    if condition != 'no-paths':
+        legacy_dir.join('repo.git/config').write('test-repo', ensure=True)
+        for lpath in LEGACY_PATHS:
+            legacy_dir.join(lpath).write(lpath, ensure=True)
+
+    git = 'echo' if condition == 'tracked' else 'git'
+
+    script = f"""
+        YADM_TEST=1 source {yadm}
+        YADM_DIR="{yadm_dir}"
+        YADM_REPO="{yadm_dir}/repo.git"
+        YADM_LEGACY_DIR="{legacy_dir}"
+        GIT_PROGRAM="{git}"
+        upgrade
+    """
+    run = runner(command=['bash'], inp=script)
+    assert run.success
+    assert run.err == ''
+    if condition == 'no-paths':
+        assert 'Upgrade is not necessary' in run.out
+    else:
+        for lpath in LEGACY_PATHS + ['repo.git']:
+            expected = (
+                f'Moving {legacy_dir.join(lpath)} '
+                f'to {yadm_dir.join(lpath)}')
+            assert expected in run.out
+        if condition == 'untracked':
+            assert 'test-repo' in yadm_dir.join('repo.git/config').read()
+            for lpath in LEGACY_PATHS:
+                assert lpath in yadm_dir.join(lpath).read()
+        elif condition == 'tracked':
+            for lpath in LEGACY_PATHS:
+                expected = (
+                    f'mv {legacy_dir.join(lpath)} '
+                    f'{yadm_dir.join(lpath)}')
+                assert expected in run.out
+            assert 'files tracked by yadm have been renamed' in run.out