tests: move templated source tests from mirror.py into separate file

Move the templated tests in tests/frontend/mirror.py into
sources/generic/mirror.py

This is part of the preparation work for #944

2 files changed, 427 insertions, 397 deletions

diff --git a/tests/frontend/mirror.py b/tests/frontend/mirror.py
index aea7f49bf..55bb8a328 100644
--- a/tests/frontend/mirror.py
+++ b/tests/frontend/mirror.py
@@ -1,7 +1,7 @@
 import os
 import pytest
 
-from tests.testutils import create_repo, ALL_REPO_KINDS, generate_junction
+from tests.testutils import create_repo, generate_junction
 
 from buildstream import _yaml
 from buildstream._exceptions import ErrorDomain
@@ -81,65 +81,6 @@ def generate_project():
 
 
 @pytest.mark.datafiles(DATA_DIR)
-@pytest.mark.parametrize("kind", [(kind) for kind in ALL_REPO_KINDS])
-def test_mirror_fetch(cli, tmpdir, datafiles, kind):
-    bin_files_path = os.path.join(str(datafiles), 'files', 'bin-files', 'usr')
-    dev_files_path = os.path.join(str(datafiles), 'files', 'dev-files', 'usr')
-    upstream_repodir = os.path.join(str(tmpdir), 'upstream')
-    mirror_repodir = os.path.join(str(tmpdir), 'mirror')
-    project_dir = os.path.join(str(tmpdir), 'project')
-    os.makedirs(project_dir)
-    element_dir = os.path.join(project_dir, 'elements')
-
-    # Create repo objects of the upstream and mirror
-    upstream_repo = create_repo(kind, upstream_repodir)
-    upstream_repo.create(bin_files_path)
-    mirror_repo = upstream_repo.copy(mirror_repodir)
-    upstream_ref = upstream_repo.create(dev_files_path)
-
-    element = {
-        'kind': 'import',
-        'sources': [
-            upstream_repo.source_config(ref=upstream_ref)
-        ]
-    }
-    element_name = 'test.bst'
-    element_path = os.path.join(element_dir, element_name)
-    full_repo = element['sources'][0]['url']
-    upstream_map, repo_name = os.path.split(full_repo)
-    alias = 'foo-' + kind
-    aliased_repo = alias + ':' + repo_name
-    element['sources'][0]['url'] = aliased_repo
-    full_mirror = mirror_repo.source_config()['url']
-    mirror_map, _ = os.path.split(full_mirror)
-    os.makedirs(element_dir)
-    _yaml.dump(element, element_path)
-
-    project = {
-        'name': 'test',
-        'element-path': 'elements',
-        'aliases': {
-            alias: upstream_map + "/"
-        },
-        'mirrors': [
-            {
-                'name': 'middle-earth',
-                'aliases': {
-                    alias: [mirror_map + "/"],
-                },
-            },
-        ]
-    }
-    project_file = os.path.join(project_dir, 'project.conf')
-    _yaml.dump(project, project_file)
-
-    # No obvious ways of checking that the mirror has been fetched
-    # But at least we can be sure it succeeds
-    result = cli.run(project=project_dir, args=['source', 'fetch', element_name])
-    result.assert_success()
-
-
-@pytest.mark.datafiles(DATA_DIR)
 @pytest.mark.parametrize("ref_storage", [("inline"), ("project.refs")])
 @pytest.mark.parametrize("mirror", [("no-mirror"), ("mirror"), ("unrelated-mirror")])
 def test_mirror_fetch_ref_storage(cli, tmpdir, datafiles, ref_storage, mirror):
@@ -215,62 +156,6 @@ def test_mirror_fetch_ref_storage(cli, tmpdir, datafiles, ref_storage, mirror):
 
 
 @pytest.mark.datafiles(DATA_DIR)
-@pytest.mark.parametrize("kind", [(kind) for kind in ALL_REPO_KINDS])
-def test_mirror_fetch_upstream_absent(cli, tmpdir, datafiles, kind):
-    dev_files_path = os.path.join(str(datafiles), 'files', 'dev-files', 'usr')
-    upstream_repodir = os.path.join(str(tmpdir), 'upstream')
-    mirror_repodir = os.path.join(str(tmpdir), 'mirror')
-    project_dir = os.path.join(str(tmpdir), 'project')
-    os.makedirs(project_dir)
-    element_dir = os.path.join(project_dir, 'elements')
-
-    # Create repo objects of the upstream and mirror
-    upstream_repo = create_repo(kind, upstream_repodir)
-    ref = upstream_repo.create(dev_files_path)
-    mirror_repo = upstream_repo.copy(mirror_repodir)
-
-    element = {
-        'kind': 'import',
-        'sources': [
-            upstream_repo.source_config(ref=ref)
-        ]
-    }
-
-    element_name = 'test.bst'
-    element_path = os.path.join(element_dir, element_name)
-    full_repo = element['sources'][0]['url']
-    upstream_map, repo_name = os.path.split(full_repo)
-    alias = 'foo-' + kind
-    aliased_repo = alias + ':' + repo_name
-    element['sources'][0]['url'] = aliased_repo
-    full_mirror = mirror_repo.source_config()['url']
-    mirror_map, _ = os.path.split(full_mirror)
-    os.makedirs(element_dir)
-    _yaml.dump(element, element_path)
-
-    project = {
-        'name': 'test',
-        'element-path': 'elements',
-        'aliases': {
-            alias: 'http://www.example.com/'
-        },
-        'mirrors': [
-            {
-                'name': 'middle-earth',
-                'aliases': {
-                    alias: [mirror_map + "/"],
-                },
-            },
-        ]
-    }
-    project_file = os.path.join(project_dir, 'project.conf')
-    _yaml.dump(project, project_file)
-
-    result = cli.run(project=project_dir, args=['source', 'fetch', element_name])
-    result.assert_success()
-
-
-@pytest.mark.datafiles(DATA_DIR)
 @pytest.mark.usefixtures("datafiles")
 def test_mirror_fetch_multi(cli, tmpdir):
     output_file = os.path.join(str(tmpdir), "output.txt")
@@ -406,287 +291,6 @@ def test_mirror_fetch_default_cmdline_overrides_config(cli, tmpdir):
 
 
 @pytest.mark.datafiles(DATA_DIR)
-@pytest.mark.parametrize("kind", [(kind) for kind in ALL_REPO_KINDS])
-def test_mirror_track_upstream_present(cli, tmpdir, datafiles, kind):
-    bin_files_path = os.path.join(str(datafiles), 'files', 'bin-files', 'usr')
-    dev_files_path = os.path.join(str(datafiles), 'files', 'dev-files', 'usr')
-    upstream_repodir = os.path.join(str(tmpdir), 'upstream')
-    mirror_repodir = os.path.join(str(tmpdir), 'mirror')
-    project_dir = os.path.join(str(tmpdir), 'project')
-    os.makedirs(project_dir)
-    element_dir = os.path.join(project_dir, 'elements')
-
-    # Create repo objects of the upstream and mirror
-    upstream_repo = create_repo(kind, upstream_repodir)
-    upstream_repo.create(bin_files_path)
-    mirror_repo = upstream_repo.copy(mirror_repodir)
-    upstream_ref = upstream_repo.create(dev_files_path)
-
-    element = {
-        'kind': 'import',
-        'sources': [
-            upstream_repo.source_config(ref=upstream_ref)
-        ]
-    }
-
-    element['sources'][0]
-    element_name = 'test.bst'
-    element_path = os.path.join(element_dir, element_name)
-    full_repo = element['sources'][0]['url']
-    upstream_map, repo_name = os.path.split(full_repo)
-    alias = 'foo-' + kind
-    aliased_repo = alias + ':' + repo_name
-    element['sources'][0]['url'] = aliased_repo
-    full_mirror = mirror_repo.source_config()['url']
-    mirror_map, _ = os.path.split(full_mirror)
-    os.makedirs(element_dir)
-    _yaml.dump(element, element_path)
-
-    project = {
-        'name': 'test',
-        'element-path': 'elements',
-        'aliases': {
-            alias: upstream_map + "/"
-        },
-        'mirrors': [
-            {
-                'name': 'middle-earth',
-                'aliases': {
-                    alias: [mirror_map + "/"],
-                },
-            },
-        ]
-    }
-    project_file = os.path.join(project_dir, 'project.conf')
-    _yaml.dump(project, project_file)
-
-    result = cli.run(project=project_dir, args=['source', 'track', element_name])
-    result.assert_success()
-
-    # Tracking tries upstream first. Check the ref is from upstream.
-    new_element = _yaml.load(element_path)
-    source = new_element['sources'][0]
-    if 'ref' in source:
-        assert source['ref'] == upstream_ref
-
-
-@pytest.mark.datafiles(DATA_DIR)
-@pytest.mark.parametrize("kind", [(kind) for kind in ALL_REPO_KINDS])
-def test_mirror_track_upstream_absent(cli, tmpdir, datafiles, kind):
-    bin_files_path = os.path.join(str(datafiles), 'files', 'bin-files', 'usr')
-    dev_files_path = os.path.join(str(datafiles), 'files', 'dev-files', 'usr')
-    upstream_repodir = os.path.join(str(tmpdir), 'upstream')
-    mirror_repodir = os.path.join(str(tmpdir), 'mirror')
-    project_dir = os.path.join(str(tmpdir), 'project')
-    os.makedirs(project_dir)
-    element_dir = os.path.join(project_dir, 'elements')
-
-    # Create repo objects of the upstream and mirror
-    upstream_repo = create_repo(kind, upstream_repodir)
-    upstream_ref = upstream_repo.create(bin_files_path)
-    mirror_repo = upstream_repo.copy(mirror_repodir)
-    mirror_ref = upstream_ref
-    upstream_ref = upstream_repo.create(dev_files_path)
-
-    element = {
-        'kind': 'import',
-        'sources': [
-            upstream_repo.source_config(ref=upstream_ref)
-        ]
-    }
-
-    element['sources'][0]
-    element_name = 'test.bst'
-    element_path = os.path.join(element_dir, element_name)
-    full_repo = element['sources'][0]['url']
-    upstream_map, repo_name = os.path.split(full_repo)
-    alias = 'foo-' + kind
-    aliased_repo = alias + ':' + repo_name
-    element['sources'][0]['url'] = aliased_repo
-    full_mirror = mirror_repo.source_config()['url']
-    mirror_map, _ = os.path.split(full_mirror)
-    os.makedirs(element_dir)
-    _yaml.dump(element, element_path)
-
-    project = {
-        'name': 'test',
-        'element-path': 'elements',
-        'aliases': {
-            alias: 'http://www.example.com/'
-        },
-        'mirrors': [
-            {
-                'name': 'middle-earth',
-                'aliases': {
-                    alias: [mirror_map + "/"],
-                },
-            },
-        ]
-    }
-    project_file = os.path.join(project_dir, 'project.conf')
-    _yaml.dump(project, project_file)
-
-    result = cli.run(project=project_dir, args=['source', 'track', element_name])
-    result.assert_success()
-
-    # Check that tracking fell back to the mirror
-    new_element = _yaml.load(element_path)
-    source = new_element['sources'][0]
-    if 'ref' in source:
-        assert source['ref'] == mirror_ref
-
-
-@pytest.mark.datafiles(DATA_DIR)
-@pytest.mark.parametrize("kind", [(kind) for kind in ALL_REPO_KINDS])
-def test_mirror_from_includes(cli, tmpdir, datafiles, kind):
-    bin_files_path = os.path.join(str(datafiles), 'files', 'bin-files', 'usr')
-    upstream_repodir = os.path.join(str(tmpdir), 'upstream')
-    mirror_repodir = os.path.join(str(tmpdir), 'mirror')
-    project_dir = os.path.join(str(tmpdir), 'project')
-    os.makedirs(project_dir)
-    element_dir = os.path.join(project_dir, 'elements')
-
-    # Create repo objects of the upstream and mirror
-    upstream_repo = create_repo(kind, upstream_repodir)
-    upstream_ref = upstream_repo.create(bin_files_path)
-    mirror_repo = upstream_repo.copy(mirror_repodir)
-
-    element = {
-        'kind': 'import',
-        'sources': [
-            upstream_repo.source_config(ref=upstream_ref)
-        ]
-    }
-    element_name = 'test.bst'
-    element_path = os.path.join(element_dir, element_name)
-    full_repo = element['sources'][0]['url']
-    upstream_map, repo_name = os.path.split(full_repo)
-    alias = 'foo-' + kind
-    aliased_repo = alias + ':' + repo_name
-    element['sources'][0]['url'] = aliased_repo
-    full_mirror = mirror_repo.source_config()['url']
-    mirror_map, _ = os.path.split(full_mirror)
-    os.makedirs(element_dir)
-    _yaml.dump(element, element_path)
-
-    config_project_dir = str(tmpdir.join('config'))
-    os.makedirs(config_project_dir, exist_ok=True)
-    config_project = {
-        'name': 'config'
-    }
-    _yaml.dump(config_project, os.path.join(config_project_dir, 'project.conf'))
-    extra_mirrors = {
-        'mirrors': [
-            {
-                'name': 'middle-earth',
-                'aliases': {
-                    alias: [mirror_map + "/"],
-                }
-            }
-        ]
-    }
-    _yaml.dump(extra_mirrors, os.path.join(config_project_dir, 'mirrors.yml'))
-    generate_junction(str(tmpdir.join('config_repo')),
-                      config_project_dir,
-                      os.path.join(element_dir, 'config.bst'))
-
-    project = {
-        'name': 'test',
-        'element-path': 'elements',
-        'aliases': {
-            alias: upstream_map + "/"
-        },
-        '(@)': [
-            'config.bst:mirrors.yml'
-        ]
-    }
-    project_file = os.path.join(project_dir, 'project.conf')
-    _yaml.dump(project, project_file)
-
-    # Now make the upstream unavailable.
-    os.rename(upstream_repo.repo, '{}.bak'.format(upstream_repo.repo))
-    result = cli.run(project=project_dir, args=['source', 'fetch', element_name])
-    result.assert_success()
-
-
-@pytest.mark.datafiles(DATA_DIR)
-@pytest.mark.parametrize("kind", [(kind) for kind in ALL_REPO_KINDS])
-def test_mirror_junction_from_includes(cli, tmpdir, datafiles, kind):
-    bin_files_path = os.path.join(str(datafiles), 'files', 'bin-files', 'usr')
-    upstream_repodir = os.path.join(str(tmpdir), 'upstream')
-    mirror_repodir = os.path.join(str(tmpdir), 'mirror')
-    project_dir = os.path.join(str(tmpdir), 'project')
-    os.makedirs(project_dir)
-    element_dir = os.path.join(project_dir, 'elements')
-
-    # Create repo objects of the upstream and mirror
-    upstream_repo = create_repo(kind, upstream_repodir)
-    upstream_ref = upstream_repo.create(bin_files_path)
-    mirror_repo = upstream_repo.copy(mirror_repodir)
-
-    element = {
-        'kind': 'junction',
-        'sources': [
-            upstream_repo.source_config(ref=upstream_ref)
-        ]
-    }
-    element_name = 'test.bst'
-    element_path = os.path.join(element_dir, element_name)
-    full_repo = element['sources'][0]['url']
-    upstream_map, repo_name = os.path.split(full_repo)
-    alias = 'foo-' + kind
-    aliased_repo = alias + ':' + repo_name
-    element['sources'][0]['url'] = aliased_repo
-    full_mirror = mirror_repo.source_config()['url']
-    mirror_map, _ = os.path.split(full_mirror)
-    os.makedirs(element_dir)
-    _yaml.dump(element, element_path)
-
-    config_project_dir = str(tmpdir.join('config'))
-    os.makedirs(config_project_dir, exist_ok=True)
-    config_project = {
-        'name': 'config'
-    }
-    _yaml.dump(config_project, os.path.join(config_project_dir, 'project.conf'))
-    extra_mirrors = {
-        'mirrors': [
-            {
-                'name': 'middle-earth',
-                'aliases': {
-                    alias: [mirror_map + "/"],
-                }
-            }
-        ]
-    }
-    _yaml.dump(extra_mirrors, os.path.join(config_project_dir, 'mirrors.yml'))
-    generate_junction(str(tmpdir.join('config_repo')),
-                      config_project_dir,
-                      os.path.join(element_dir, 'config.bst'))
-
-    project = {
-        'name': 'test',
-        'element-path': 'elements',
-        'aliases': {
-            alias: upstream_map + "/"
-        },
-        '(@)': [
-            'config.bst:mirrors.yml'
-        ]
-    }
-    project_file = os.path.join(project_dir, 'project.conf')
-    _yaml.dump(project, project_file)
-
-    # Now make the upstream unavailable.
-    os.rename(upstream_repo.repo, '{}.bak'.format(upstream_repo.repo))
-    result = cli.run(project=project_dir, args=['source', 'fetch', element_name])
-    result.assert_main_error(ErrorDomain.STREAM, None)
-    # Now make the upstream available again.
-    os.rename('{}.bak'.format(upstream_repo.repo), upstream_repo.repo)
-    result = cli.run(project=project_dir, args=['source', 'fetch', element_name])
-    result.assert_success()
-
-
-@pytest.mark.datafiles(DATA_DIR)
 def test_mirror_git_submodule_fetch(cli, tmpdir, datafiles):
     # Test that it behaves as expected with submodules, both defined in config
     # and discovered when fetching.
diff --git a/tests/sources/generic/mirror.py b/tests/sources/generic/mirror.py
new file mode 100644
index 000000000..63571234e
--- /dev/null
+++ b/tests/sources/generic/mirror.py
@@ -0,0 +1,426 @@
+#
+#  Copyright (C) 2018 Codethink Limited
+#  Copyright (C) 2019 Bloomberg Finance LP
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU Lesser General Public
+#  License as published by the Free Software Foundation; either
+#  version 2 of the License, or (at your option) any later version.
+#
+#  This library is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+#  Lesser General Public License for more details.
+#
+#  You should have received a copy of the GNU Lesser General Public
+#  License along with this library. If not, see <http://www.gnu.org/licenses/>.
+#
+
+import os
+import pytest
+
+from tests.testutils import create_repo, ALL_REPO_KINDS, generate_junction
+
+from buildstream.plugintestutils import cli
+from buildstream import _yaml
+from buildstream._exceptions import ErrorDomain
+
+# Project directory
+TOP_DIR = os.path.dirname(os.path.realpath(__file__))
+DATA_DIR = os.path.join(TOP_DIR, 'project')
+
+
+@pytest.mark.datafiles(DATA_DIR)
+@pytest.mark.parametrize("kind", [(kind) for kind in ALL_REPO_KINDS])
+def test_mirror_fetch(cli, tmpdir, datafiles, kind):
+    bin_files_path = os.path.join(str(datafiles), 'files', 'bin-files', 'usr')
+    dev_files_path = os.path.join(str(datafiles), 'files', 'dev-files', 'usr')
+    upstream_repodir = os.path.join(str(tmpdir), 'upstream')
+    mirror_repodir = os.path.join(str(tmpdir), 'mirror')
+    project_dir = os.path.join(str(tmpdir), 'project')
+    os.makedirs(project_dir)
+    element_dir = os.path.join(project_dir, 'elements')
+
+    # Create repo objects of the upstream and mirror
+    upstream_repo = create_repo(kind, upstream_repodir)
+    upstream_repo.create(bin_files_path)
+    mirror_repo = upstream_repo.copy(mirror_repodir)
+    upstream_ref = upstream_repo.create(dev_files_path)
+
+    element = {
+        'kind': 'import',
+        'sources': [
+            upstream_repo.source_config(ref=upstream_ref)
+        ]
+    }
+    element_name = 'test.bst'
+    element_path = os.path.join(element_dir, element_name)
+    full_repo = element['sources'][0]['url']
+    upstream_map, repo_name = os.path.split(full_repo)
+    alias = 'foo-' + kind
+    aliased_repo = alias + ':' + repo_name
+    element['sources'][0]['url'] = aliased_repo
+    full_mirror = mirror_repo.source_config()['url']
+    mirror_map, _ = os.path.split(full_mirror)
+    os.makedirs(element_dir)
+    _yaml.dump(element, element_path)
+
+    project = {
+        'name': 'test',
+        'element-path': 'elements',
+        'aliases': {
+            alias: upstream_map + "/"
+        },
+        'mirrors': [
+            {
+                'name': 'middle-earth',
+                'aliases': {
+                    alias: [mirror_map + "/"],
+                },
+            },
+        ]
+    }
+    project_file = os.path.join(project_dir, 'project.conf')
+    _yaml.dump(project, project_file)
+
+    # No obvious ways of checking that the mirror has been fetched
+    # But at least we can be sure it succeeds
+    result = cli.run(project=project_dir, args=['source', 'fetch', element_name])
+    result.assert_success()
+
+
+@pytest.mark.datafiles(DATA_DIR)
+@pytest.mark.parametrize("kind", [(kind) for kind in ALL_REPO_KINDS])
+def test_mirror_fetch_upstream_absent(cli, tmpdir, datafiles, kind):
+    dev_files_path = os.path.join(str(datafiles), 'files', 'dev-files', 'usr')
+    upstream_repodir = os.path.join(str(tmpdir), 'upstream')
+    mirror_repodir = os.path.join(str(tmpdir), 'mirror')
+    project_dir = os.path.join(str(tmpdir), 'project')
+    os.makedirs(project_dir)
+    element_dir = os.path.join(project_dir, 'elements')
+
+    # Create repo objects of the upstream and mirror
+    upstream_repo = create_repo(kind, upstream_repodir)
+    ref = upstream_repo.create(dev_files_path)
+    mirror_repo = upstream_repo.copy(mirror_repodir)
+
+    element = {
+        'kind': 'import',
+        'sources': [
+            upstream_repo.source_config(ref=ref)
+        ]
+    }
+
+    element_name = 'test.bst'
+    element_path = os.path.join(element_dir, element_name)
+    full_repo = element['sources'][0]['url']
+    upstream_map, repo_name = os.path.split(full_repo)
+    alias = 'foo-' + kind
+    aliased_repo = alias + ':' + repo_name
+    element['sources'][0]['url'] = aliased_repo
+    full_mirror = mirror_repo.source_config()['url']
+    mirror_map, _ = os.path.split(full_mirror)
+    os.makedirs(element_dir)
+    _yaml.dump(element, element_path)
+
+    project = {
+        'name': 'test',
+        'element-path': 'elements',
+        'aliases': {
+            alias: 'http://www.example.com/'
+        },
+        'mirrors': [
+            {
+                'name': 'middle-earth',
+                'aliases': {
+                    alias: [mirror_map + "/"],
+                },
+            },
+        ]
+    }
+    project_file = os.path.join(project_dir, 'project.conf')
+    _yaml.dump(project, project_file)
+
+    result = cli.run(project=project_dir, args=['source', 'fetch', element_name])
+    result.assert_success()
+
+
+@pytest.mark.datafiles(DATA_DIR)
+@pytest.mark.parametrize("kind", [(kind) for kind in ALL_REPO_KINDS])
+def test_mirror_from_includes(cli, tmpdir, datafiles, kind):
+    bin_files_path = os.path.join(str(datafiles), 'files', 'bin-files', 'usr')
+    upstream_repodir = os.path.join(str(tmpdir), 'upstream')
+    mirror_repodir = os.path.join(str(tmpdir), 'mirror')
+    project_dir = os.path.join(str(tmpdir), 'project')
+    os.makedirs(project_dir)
+    element_dir = os.path.join(project_dir, 'elements')
+
+    # Create repo objects of the upstream and mirror
+    upstream_repo = create_repo(kind, upstream_repodir)
+    upstream_ref = upstream_repo.create(bin_files_path)
+    mirror_repo = upstream_repo.copy(mirror_repodir)
+
+    element = {
+        'kind': 'import',
+        'sources': [
+            upstream_repo.source_config(ref=upstream_ref)
+        ]
+    }
+    element_name = 'test.bst'
+    element_path = os.path.join(element_dir, element_name)
+    full_repo = element['sources'][0]['url']
+    upstream_map, repo_name = os.path.split(full_repo)
+    alias = 'foo-' + kind
+    aliased_repo = alias + ':' + repo_name
+    element['sources'][0]['url'] = aliased_repo
+    full_mirror = mirror_repo.source_config()['url']
+    mirror_map, _ = os.path.split(full_mirror)
+    os.makedirs(element_dir)
+    _yaml.dump(element, element_path)
+
+    config_project_dir = str(tmpdir.join('config'))
+    os.makedirs(config_project_dir, exist_ok=True)
+    config_project = {
+        'name': 'config'
+    }
+    _yaml.dump(config_project, os.path.join(config_project_dir, 'project.conf'))
+    extra_mirrors = {
+        'mirrors': [
+            {
+                'name': 'middle-earth',
+                'aliases': {
+                    alias: [mirror_map + "/"],
+                }
+            }
+        ]
+    }
+    _yaml.dump(extra_mirrors, os.path.join(config_project_dir, 'mirrors.yml'))
+    generate_junction(str(tmpdir.join('config_repo')),
+                      config_project_dir,
+                      os.path.join(element_dir, 'config.bst'))
+
+    project = {
+        'name': 'test',
+        'element-path': 'elements',
+        'aliases': {
+            alias: upstream_map + "/"
+        },
+        '(@)': [
+            'config.bst:mirrors.yml'
+        ]
+    }
+    project_file = os.path.join(project_dir, 'project.conf')
+    _yaml.dump(project, project_file)
+
+    # Now make the upstream unavailable.
+    os.rename(upstream_repo.repo, '{}.bak'.format(upstream_repo.repo))
+    result = cli.run(project=project_dir, args=['source', 'fetch', element_name])
+    result.assert_success()
+
+
+@pytest.mark.datafiles(DATA_DIR)
+@pytest.mark.parametrize("kind", [(kind) for kind in ALL_REPO_KINDS])
+def test_mirror_junction_from_includes(cli, tmpdir, datafiles, kind):
+    bin_files_path = os.path.join(str(datafiles), 'files', 'bin-files', 'usr')
+    upstream_repodir = os.path.join(str(tmpdir), 'upstream')
+    mirror_repodir = os.path.join(str(tmpdir), 'mirror')
+    project_dir = os.path.join(str(tmpdir), 'project')
+    os.makedirs(project_dir)
+    element_dir = os.path.join(project_dir, 'elements')
+
+    # Create repo objects of the upstream and mirror
+    upstream_repo = create_repo(kind, upstream_repodir)
+    upstream_ref = upstream_repo.create(bin_files_path)
+    mirror_repo = upstream_repo.copy(mirror_repodir)
+
+    element = {
+        'kind': 'junction',
+        'sources': [
+            upstream_repo.source_config(ref=upstream_ref)
+        ]
+    }
+    element_name = 'test.bst'
+    element_path = os.path.join(element_dir, element_name)
+    full_repo = element['sources'][0]['url']
+    upstream_map, repo_name = os.path.split(full_repo)
+    alias = 'foo-' + kind
+    aliased_repo = alias + ':' + repo_name
+    element['sources'][0]['url'] = aliased_repo
+    full_mirror = mirror_repo.source_config()['url']
+    mirror_map, _ = os.path.split(full_mirror)
+    os.makedirs(element_dir)
+    _yaml.dump(element, element_path)
+
+    config_project_dir = str(tmpdir.join('config'))
+    os.makedirs(config_project_dir, exist_ok=True)
+    config_project = {
+        'name': 'config'
+    }
+    _yaml.dump(config_project, os.path.join(config_project_dir, 'project.conf'))
+    extra_mirrors = {
+        'mirrors': [
+            {
+                'name': 'middle-earth',
+                'aliases': {
+                    alias: [mirror_map + "/"],
+                }
+            }
+        ]
+    }
+    _yaml.dump(extra_mirrors, os.path.join(config_project_dir, 'mirrors.yml'))
+    generate_junction(str(tmpdir.join('config_repo')),
+                      config_project_dir,
+                      os.path.join(element_dir, 'config.bst'))
+
+    project = {
+        'name': 'test',
+        'element-path': 'elements',
+        'aliases': {
+            alias: upstream_map + "/"
+        },
+        '(@)': [
+            'config.bst:mirrors.yml'
+        ]
+    }
+    project_file = os.path.join(project_dir, 'project.conf')
+    _yaml.dump(project, project_file)
+
+    # Now make the upstream unavailable.
+    os.rename(upstream_repo.repo, '{}.bak'.format(upstream_repo.repo))
+    result = cli.run(project=project_dir, args=['source', 'fetch', element_name])
+    result.assert_main_error(ErrorDomain.STREAM, None)
+    # Now make the upstream available again.
+    os.rename('{}.bak'.format(upstream_repo.repo), upstream_repo.repo)
+    result = cli.run(project=project_dir, args=['source', 'fetch', element_name])
+    result.assert_success()
+
+
+@pytest.mark.datafiles(DATA_DIR)
+@pytest.mark.parametrize("kind", [(kind) for kind in ALL_REPO_KINDS])
+def test_mirror_track_upstream_present(cli, tmpdir, datafiles, kind):
+    bin_files_path = os.path.join(str(datafiles), 'files', 'bin-files', 'usr')
+    dev_files_path = os.path.join(str(datafiles), 'files', 'dev-files', 'usr')
+    upstream_repodir = os.path.join(str(tmpdir), 'upstream')
+    mirror_repodir = os.path.join(str(tmpdir), 'mirror')
+    project_dir = os.path.join(str(tmpdir), 'project')
+    os.makedirs(project_dir)
+    element_dir = os.path.join(project_dir, 'elements')
+
+    # Create repo objects of the upstream and mirror
+    upstream_repo = create_repo(kind, upstream_repodir)
+    upstream_repo.create(bin_files_path)
+    mirror_repo = upstream_repo.copy(mirror_repodir)
+    upstream_ref = upstream_repo.create(dev_files_path)
+
+    element = {
+        'kind': 'import',
+        'sources': [
+            upstream_repo.source_config(ref=upstream_ref)
+        ]
+    }
+
+    element['sources'][0]
+    element_name = 'test.bst'
+    element_path = os.path.join(element_dir, element_name)
+    full_repo = element['sources'][0]['url']
+    upstream_map, repo_name = os.path.split(full_repo)
+    alias = 'foo-' + kind
+    aliased_repo = alias + ':' + repo_name
+    element['sources'][0]['url'] = aliased_repo
+    full_mirror = mirror_repo.source_config()['url']
+    mirror_map, _ = os.path.split(full_mirror)
+    os.makedirs(element_dir)
+    _yaml.dump(element, element_path)
+
+    project = {
+        'name': 'test',
+        'element-path': 'elements',
+        'aliases': {
+            alias: upstream_map + "/"
+        },
+        'mirrors': [
+            {
+                'name': 'middle-earth',
+                'aliases': {
+                    alias: [mirror_map + "/"],
+                },
+            },
+        ]
+    }
+    project_file = os.path.join(project_dir, 'project.conf')
+    _yaml.dump(project, project_file)
+
+    result = cli.run(project=project_dir, args=['source', 'track', element_name])
+    result.assert_success()
+
+    # Tracking tries upstream first. Check the ref is from upstream.
+    new_element = _yaml.load(element_path)
+    source = new_element['sources'][0]
+    if 'ref' in source:
+        assert source['ref'] == upstream_ref
+
+
+@pytest.mark.datafiles(DATA_DIR)
+@pytest.mark.parametrize("kind", [(kind) for kind in ALL_REPO_KINDS])
+def test_mirror_track_upstream_absent(cli, tmpdir, datafiles, kind):
+    bin_files_path = os.path.join(str(datafiles), 'files', 'bin-files', 'usr')
+    dev_files_path = os.path.join(str(datafiles), 'files', 'dev-files', 'usr')
+    upstream_repodir = os.path.join(str(tmpdir), 'upstream')
+    mirror_repodir = os.path.join(str(tmpdir), 'mirror')
+    project_dir = os.path.join(str(tmpdir), 'project')
+    os.makedirs(project_dir)
+    element_dir = os.path.join(project_dir, 'elements')
+
+    # Create repo objects of the upstream and mirror
+    upstream_repo = create_repo(kind, upstream_repodir)
+    upstream_ref = upstream_repo.create(bin_files_path)
+    mirror_repo = upstream_repo.copy(mirror_repodir)
+    mirror_ref = upstream_ref
+    upstream_ref = upstream_repo.create(dev_files_path)
+
+    element = {
+        'kind': 'import',
+        'sources': [
+            upstream_repo.source_config(ref=upstream_ref)
+        ]
+    }
+
+    element['sources'][0]
+    element_name = 'test.bst'
+    element_path = os.path.join(element_dir, element_name)
+    full_repo = element['sources'][0]['url']
+    upstream_map, repo_name = os.path.split(full_repo)
+    alias = 'foo-' + kind
+    aliased_repo = alias + ':' + repo_name
+    element['sources'][0]['url'] = aliased_repo
+    full_mirror = mirror_repo.source_config()['url']
+    mirror_map, _ = os.path.split(full_mirror)
+    os.makedirs(element_dir)
+    _yaml.dump(element, element_path)
+
+    project = {
+        'name': 'test',
+        'element-path': 'elements',
+        'aliases': {
+            alias: 'http://www.example.com/'
+        },
+        'mirrors': [
+            {
+                'name': 'middle-earth',
+                'aliases': {
+                    alias: [mirror_map + "/"],
+                },
+            },
+        ]
+    }
+    project_file = os.path.join(project_dir, 'project.conf')
+    _yaml.dump(project, project_file)
+
+    result = cli.run(project=project_dir, args=['source', 'track', element_name])
+    result.assert_success()
+
+    # Check that tracking fell back to the mirror
+    new_element = _yaml.load(element_path)
+    source = new_element['sources'][0]
+    if 'ref' in source:
+        assert source['ref'] == mirror_ref