From 3ae24057522c458d78dcb006d02b90bb205444da Mon Sep 17 00:00:00 2001
From: Thomas Coldrick <thomas.coldrick@codethink.co.uk>
Date: Mon, 20 Jan 2020 09:28:28 +0000
Subject: testing: Add functions to generate yaml files

Adds functions to the `buildstream.testing` package to allow plugins to
dump elements and projects on the fly. Before this plugins were just
accessing the private yaml API for tests and loading/dumping directly. I
also allow access to just `_yaml.load()` from testing.
---
 src/buildstream/testing/__init__.py     |  2 +
 src/buildstream/testing/_yaml.py        | 19 +++++++
 tests/sources/bzr.py                    |  5 +-
 tests/sources/git.py                    | 97 +++++++++++++++------------------
 tests/sources/no_fetch_cached.py        |  5 +-
 tests/sources/pip.py                    |  8 +--
 tests/sources/previous_source_access.py |  6 +-
 tests/sources/remote.py                 | 34 +++++-------
 tests/sources/tar.py                    | 48 +++++++---------
 tests/sources/zip.py                    | 28 +++-------
 10 files changed, 116 insertions(+), 136 deletions(-)
 create mode 100644 src/buildstream/testing/_yaml.py

diff --git a/src/buildstream/testing/__init__.py b/src/buildstream/testing/__init__.py
index 46cadbbfa..dafc3a9fe 100644
--- a/src/buildstream/testing/__init__.py
+++ b/src/buildstream/testing/__init__.py
@@ -22,6 +22,8 @@ This package contains various utilities which make it easier to test plugins.
 import os
 from collections import OrderedDict
 from buildstream.exceptions import ErrorDomain, LoadErrorReason
+from buildstream._yaml import load as load_yaml  # type: ignore
+from ._yaml import generate_project, generate_element
 from .repo import Repo
 from .runcli import cli, cli_integration, cli_remote_execution
 from .integration import integration_cache
diff --git a/src/buildstream/testing/_yaml.py b/src/buildstream/testing/_yaml.py
new file mode 100644
index 000000000..ccf65a1ae
--- /dev/null
+++ b/src/buildstream/testing/_yaml.py
@@ -0,0 +1,19 @@
+import os
+
+from buildstream._yaml import roundtrip_dump  # type: ignore
+
+
+def generate_project(project_dir, config=None):
+    if config is None:
+        config = {}
+    project_file = os.path.join(project_dir, "project.conf")
+    if "name" not in config:
+        config["name"] = os.path.basename(project_dir)
+    roundtrip_dump(config, project_file)
+
+
+def generate_element(element_dir, element_name, config=None):
+    if config is None:
+        config = {}
+    element_path = os.path.join(element_dir, element_name)
+    roundtrip_dump(config, element_path)
diff --git a/tests/sources/bzr.py b/tests/sources/bzr.py
index ca727c793..2dcacfef5 100644
--- a/tests/sources/bzr.py
+++ b/tests/sources/bzr.py
@@ -4,10 +4,9 @@
 import os
 import pytest
 
-from buildstream import _yaml
-
 from buildstream.testing import cli  # pylint: disable=unused-import
 from buildstream.testing import create_repo
+from buildstream.testing import generate_element
 from buildstream.testing._utils.site import HAVE_BZR
 
 DATA_DIR = os.path.join(os.path.dirname(os.path.realpath(__file__)), "bzr")
@@ -24,7 +23,7 @@ def test_fetch_checkout(cli, tmpdir, datafiles):
 
     # Write out our test target
     element = {"kind": "import", "sources": [repo.source_config(ref=ref)]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # Fetch, build, checkout
     result = cli.run(project=project, args=["source", "fetch", "target.bst"])
diff --git a/tests/sources/git.py b/tests/sources/git.py
index 1176c8ffd..25ec49347 100644
--- a/tests/sources/git.py
+++ b/tests/sources/git.py
@@ -29,10 +29,11 @@ import shutil
 
 import pytest
 
-from buildstream import _yaml, Node
+from buildstream import Node
 from buildstream.exceptions import ErrorDomain
 from buildstream.plugin import CoreWarnings
 from buildstream.testing import cli  # pylint: disable=unused-import
+from buildstream.testing import generate_project, generate_element, load_yaml
 from buildstream.testing import create_repo
 from buildstream.testing._utils.site import HAVE_GIT, HAVE_OLD_GIT
 
@@ -50,7 +51,7 @@ def test_fetch_bad_ref(cli, tmpdir, datafiles):
 
     # Write out our test target with a bad ref
     element = {"kind": "import", "sources": [repo.source_config(ref="5")]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # Assert that fetch raises an error here
     result = cli.run(project=project, args=["source", "fetch", "target.bst"])
@@ -77,7 +78,7 @@ def test_submodule_fetch_checkout(cli, tmpdir, datafiles):
 
     # Write out our test target
     element = {"kind": "import", "sources": [repo.source_config(ref=ref)]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # Fetch, build, checkout
     result = cli.run(project=project, args=["source", "fetch", "target.bst"])
@@ -116,7 +117,7 @@ def test_recursive_submodule_fetch_checkout(cli, tmpdir, datafiles):
 
     # Write out our test target
     element = {"kind": "import", "sources": [repo.source_config(ref=ref)]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # Fetch, build, checkout
     result = cli.run(project=project, args=["source", "fetch", "target.bst"])
@@ -151,7 +152,7 @@ def test_submodule_fetch_source_enable_explicit(cli, tmpdir, datafiles):
 
     # Write out our test target
     element = {"kind": "import", "sources": [repo.source_config_extra(ref=ref, checkout_submodules=True)]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # Fetch, build, checkout
     result = cli.run(project=project, args=["source", "fetch", "target.bst"])
@@ -185,7 +186,7 @@ def test_submodule_fetch_source_disable(cli, tmpdir, datafiles):
 
     # Write out our test target
     element = {"kind": "import", "sources": [repo.source_config_extra(ref=ref, checkout_submodules=False)]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # Fetch, build, checkout
     result = cli.run(project=project, args=["source", "fetch", "target.bst"])
@@ -219,7 +220,7 @@ def test_submodule_fetch_submodule_does_override(cli, tmpdir, datafiles):
 
     # Write out our test target
     element = {"kind": "import", "sources": [repo.source_config_extra(ref=ref, checkout_submodules=False)]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # Fetch, build, checkout
     result = cli.run(project=project, args=["source", "fetch", "target.bst"])
@@ -258,7 +259,7 @@ def test_submodule_fetch_submodule_individual_checkout(cli, tmpdir, datafiles):
 
     # Write out our test target
     element = {"kind": "import", "sources": [repo.source_config_extra(ref=ref, checkout_submodules=True)]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # Fetch, build, checkout
     result = cli.run(project=project, args=["source", "fetch", "target.bst"])
@@ -298,7 +299,7 @@ def test_submodule_fetch_submodule_individual_checkout_explicit(cli, tmpdir, dat
 
     # Write out our test target
     element = {"kind": "import", "sources": [repo.source_config_extra(ref=ref, checkout_submodules=True)]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # Fetch, build, checkout
     result = cli.run(project=project, args=["source", "fetch", "target.bst"])
@@ -333,7 +334,7 @@ def test_submodule_fetch_project_override(cli, tmpdir, datafiles):
 
     # Write out our test target
     element = {"kind": "import", "sources": [repo.source_config(ref=ref)]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # Fetch, build, checkout
     result = cli.run(project=project, args=["source", "fetch", "target.bst"])
@@ -359,7 +360,7 @@ def test_submodule_track_ignore_inconsistent(cli, tmpdir, datafiles):
 
     # Write out our test target
     element = {"kind": "import", "sources": [repo.source_config(ref=ref)]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # Now add a .gitmodules file with an inconsistent submodule,
     # we are calling this inconsistent because the file was created
@@ -393,8 +394,7 @@ def test_submodule_track_no_ref_or_track(cli, tmpdir, datafiles):
     gitsource = repo.source_config(ref=None)
     gitsource.pop("track")
     element = {"kind": "import", "sources": [gitsource]}
-
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # Track will encounter an inconsistent submodule without any ref
     result = cli.run(project=project, args=["show", "target.bst"])
@@ -410,8 +410,7 @@ def test_ref_not_in_track(cli, tmpdir, datafiles, fail):
 
     # Make the warning an error if we're testing errors
     if fail == "error":
-        project_template = {"name": "foo", "fatal-warnings": [CoreWarnings.REF_NOT_IN_TRACK]}
-        _yaml.roundtrip_dump(project_template, os.path.join(project, "project.conf"))
+        generate_project(project, config={"fatal-warnings": [CoreWarnings.REF_NOT_IN_TRACK]})
 
     # Create the repo from 'repofiles', create a branch without latest commit
     repo = create_repo("git", str(tmpdir))
@@ -424,7 +423,7 @@ def test_ref_not_in_track(cli, tmpdir, datafiles, fail):
 
     # Write out our test target
     element = {"kind": "import", "sources": [gitsource]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     result = cli.run(project=project, args=["build", "target.bst"])
 
@@ -445,8 +444,7 @@ def test_unlisted_submodule(cli, tmpdir, datafiles, fail):
 
     # Make the warning an error if we're testing errors
     if fail == "error":
-        project_template = {"name": "foo", "fatal-warnings": ["git:unlisted-submodule"]}
-        _yaml.roundtrip_dump(project_template, os.path.join(project, "project.conf"))
+        generate_project(project, config={"fatal-warnings": ["git:unlisted-submodule"]})
 
     # Create the submodule first from the 'subrepofiles' subdir
     subrepo = create_repo("git", str(tmpdir), "subrepo")
@@ -470,7 +468,7 @@ def test_unlisted_submodule(cli, tmpdir, datafiles, fail):
 
     # Write out our test target
     element = {"kind": "import", "sources": [gitsource]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # We will not see the warning or error before the first fetch, because
     # we don't have the repository yet and so we have no knowledge of
@@ -512,8 +510,7 @@ def test_track_unlisted_submodule(cli, tmpdir, datafiles, fail):
 
     # Make the warning an error if we're testing errors
     if fail == "error":
-        project_template = {"name": "foo", "fatal-warnings": ["git:unlisted-submodule"]}
-        _yaml.roundtrip_dump(project_template, os.path.join(project, "project.conf"))
+        generate_project(project, config={"fatal-warnings": ["git:unlisted-submodule"]})
 
     # Create the submodule first from the 'subrepofiles' subdir
     subrepo = create_repo("git", str(tmpdir), "subrepo")
@@ -534,7 +531,7 @@ def test_track_unlisted_submodule(cli, tmpdir, datafiles, fail):
 
     # Write out our test target
     element = {"kind": "import", "sources": [gitsource]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # Fetch the repo, we will not see the warning because we
     # are still pointing to a ref which predates the submodules
@@ -567,8 +564,7 @@ def test_invalid_submodule(cli, tmpdir, datafiles, fail):
 
     # Make the warning an error if we're testing errors
     if fail == "error":
-        project_template = {"name": "foo", "fatal-warnings": ["git:invalid-submodule"]}
-        _yaml.roundtrip_dump(project_template, os.path.join(project, "project.conf"))
+        generate_project(project, config={"fatal-warnings": ["git:invalid-submodule"]})
 
     # Create the repo from 'repofiles' subdir
     repo = create_repo("git", str(tmpdir))
@@ -586,7 +582,7 @@ def test_invalid_submodule(cli, tmpdir, datafiles, fail):
 
     # Write out our test target
     element = {"kind": "import", "sources": [gitsource]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # We will not see the warning or error before the first fetch, because
     # we don't have the repository yet and so we have no knowledge of
@@ -629,8 +625,7 @@ def test_track_invalid_submodule(cli, tmpdir, datafiles, fail):
 
     # Make the warning an error if we're testing errors
     if fail == "error":
-        project_template = {"name": "foo", "fatal-warnings": ["git:invalid-submodule"]}
-        _yaml.roundtrip_dump(project_template, os.path.join(project, "project.conf"))
+        generate_project(project, config={"fatal-warnings": ["git:invalid-submodule"]})
 
     # Create the submodule first from the 'subrepofiles' subdir
     subrepo = create_repo("git", str(tmpdir), "subrepo")
@@ -652,7 +647,7 @@ def test_track_invalid_submodule(cli, tmpdir, datafiles, fail):
 
     # Write out our test target
     element = {"kind": "import", "sources": [gitsource]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # Fetch the repo, we will not see the warning because we
     # are still pointing to a ref which predates the submodules
@@ -692,14 +687,14 @@ def test_track_fetch(cli, tmpdir, datafiles, ref_format, tag, extra_commit):
     # Write out our test target
     element = {"kind": "import", "sources": [repo.source_config()]}
     element["sources"][0]["ref-format"] = ref_format
+    generate_element(project, "target.bst", element)
     element_path = os.path.join(project, "target.bst")
-    _yaml.roundtrip_dump(element, element_path)
 
     # Track it
     result = cli.run(project=project, args=["source", "track", "target.bst"])
     result.assert_success()
 
-    element = _yaml.load(element_path)
+    element = load_yaml(element_path)
     new_ref = element.get_sequence("sources").mapping_at(0).get_str("ref")
 
     if ref_format == "git-describe" and tag:
@@ -724,9 +719,9 @@ def test_track_fetch(cli, tmpdir, datafiles, ref_format, tag, extra_commit):
 def test_git_describe(cli, tmpdir, datafiles, ref_storage, tag_type):
     project = str(datafiles)
 
-    project_config = _yaml.load(os.path.join(project, "project.conf"))
+    project_config = load_yaml(os.path.join(project, "project.conf"))
     project_config["ref-storage"] = ref_storage
-    _yaml.roundtrip_dump(project_config, os.path.join(project, "project.conf"))
+    generate_project(project, config=project_config)
 
     repofiles = os.path.join(str(tmpdir), "repofiles")
     os.makedirs(repofiles, exist_ok=True)
@@ -775,8 +770,8 @@ def test_git_describe(cli, tmpdir, datafiles, ref_storage, tag_type):
         "kind": "import",
         "sources": [config],
     }
+    generate_element(project, "target.bst", element)
     element_path = os.path.join(project, "target.bst")
-    _yaml.roundtrip_dump(element, element_path)
 
     if ref_storage == "inline":
         result = cli.run(project=project, args=["source", "track", "target.bst"])
@@ -786,7 +781,7 @@ def test_git_describe(cli, tmpdir, datafiles, ref_storage, tag_type):
         result.assert_success()
 
     if ref_storage == "inline":
-        element = _yaml.load(element_path)
+        element = load_yaml(element_path)
         tags = element.get_sequence("sources").mapping_at(0).get_sequence("tags")
         assert len(tags) == 2
         for tag in tags:
@@ -834,9 +829,9 @@ def test_git_describe(cli, tmpdir, datafiles, ref_storage, tag_type):
 def test_git_describe_head_is_tagged(cli, tmpdir, datafiles, ref_storage, tag_type):
     project = str(datafiles)
 
-    project_config = _yaml.load(os.path.join(project, "project.conf"))
+    project_config = load_yaml(os.path.join(project, "project.conf"))
     project_config["ref-storage"] = ref_storage
-    _yaml.roundtrip_dump(project_config, os.path.join(project, "project.conf"))
+    generate_project(project, config=project_config)
 
     repofiles = os.path.join(str(tmpdir), "repofiles")
     os.makedirs(repofiles, exist_ok=True)
@@ -884,8 +879,8 @@ def test_git_describe_head_is_tagged(cli, tmpdir, datafiles, ref_storage, tag_ty
         "kind": "import",
         "sources": [config],
     }
+    generate_element(project, "target.bst", element)
     element_path = os.path.join(project, "target.bst")
-    _yaml.roundtrip_dump(element, element_path)
 
     if ref_storage == "inline":
         result = cli.run(project=project, args=["source", "track", "target.bst"])
@@ -895,7 +890,7 @@ def test_git_describe_head_is_tagged(cli, tmpdir, datafiles, ref_storage, tag_ty
         result.assert_success()
 
     if ref_storage == "inline":
-        element = _yaml.load(element_path)
+        element = load_yaml(element_path)
         source = element.get_sequence("sources").mapping_at(0)
         tags = source.get_sequence("tags")
         assert len(tags) == 1
@@ -941,9 +936,9 @@ def test_git_describe_head_is_tagged(cli, tmpdir, datafiles, ref_storage, tag_ty
 def test_git_describe_relevant_history(cli, tmpdir, datafiles):
     project = str(datafiles)
 
-    project_config = _yaml.load(os.path.join(project, "project.conf"))
+    project_config = load_yaml(os.path.join(project, "project.conf"))
     project_config["ref-storage"] = "project.refs"
-    _yaml.roundtrip_dump(project_config, os.path.join(project, "project.conf"))
+    generate_project(project, config=project_config)
 
     repofiles = os.path.join(str(tmpdir), "repofiles")
     os.makedirs(repofiles, exist_ok=True)
@@ -989,8 +984,7 @@ def test_git_describe_relevant_history(cli, tmpdir, datafiles):
         "kind": "import",
         "sources": [config],
     }
-    element_path = os.path.join(project, "target.bst")
-    _yaml.roundtrip_dump(element, element_path)
+    generate_element(project, "target.bst", element)
 
     result = cli.run(project=project, args=["source", "track", "target.bst", "--deps", "all"])
     result.assert_success()
@@ -1015,9 +1009,9 @@ def test_git_describe_relevant_history(cli, tmpdir, datafiles):
 def test_default_do_not_track_tags(cli, tmpdir, datafiles):
     project = str(datafiles)
 
-    project_config = _yaml.load(os.path.join(project, "project.conf"))
+    project_config = load_yaml(os.path.join(project, "project.conf"))
     project_config["ref-storage"] = "inline"
-    _yaml.roundtrip_dump(project_config, os.path.join(project, "project.conf"))
+    generate_project(project, config=project_config)
 
     repofiles = os.path.join(str(tmpdir), "repofiles")
     os.makedirs(repofiles, exist_ok=True)
@@ -1038,13 +1032,13 @@ def test_default_do_not_track_tags(cli, tmpdir, datafiles):
         "kind": "import",
         "sources": [config],
     }
+    generate_element(project, "target.bst", element)
     element_path = os.path.join(project, "target.bst")
-    _yaml.roundtrip_dump(element, element_path)
 
     result = cli.run(project=project, args=["source", "track", "target.bst"])
     result.assert_success()
 
-    element = _yaml.load(element_path)
+    element = load_yaml(element_path)
     source = element.get_sequence("sources").mapping_at(0)
     assert "tags" not in source
 
@@ -1070,10 +1064,10 @@ def test_overwrite_rogue_tag_multiple_remotes(cli, tmpdir, datafiles):
     top_commit = repo.create(repofiles)
 
     repodir, reponame = os.path.split(repo.repo)
-    project_config = _yaml.load(os.path.join(project, "project.conf"))
+    project_config = load_yaml(os.path.join(project, "project.conf"))
     project_config["aliases"] = Node.from_dict({"repo": "http://example.com/"})
     project_config["mirrors"] = [{"name": "middle-earth", "aliases": {"repo": ["file://{}/".format(repodir)]}}]
-    _yaml.roundtrip_dump(project_config, os.path.join(project, "project.conf"))
+    generate_project(project, config=project_config)
 
     repo.add_annotated_tag("tag", "tag")
 
@@ -1092,8 +1086,7 @@ def test_overwrite_rogue_tag_multiple_remotes(cli, tmpdir, datafiles):
         "kind": "import",
         "sources": [config],
     }
-    element_path = os.path.join(project, "target.bst")
-    _yaml.roundtrip_dump(element, element_path)
+    generate_element(project, "target.bst", element)
 
     result = cli.run(project=project, args=["build", "target.bst"])
     result.assert_success()
@@ -1116,7 +1109,7 @@ def test_overwrite_rogue_tag_multiple_remotes(cli, tmpdir, datafiles):
 
     repodir, reponame = os.path.split(repo.repo)
 
-    _yaml.roundtrip_dump(project_config, os.path.join(project, "project.conf"))
+    generate_project(project, config=project_config)
 
     config = repo.source_config(ref=new_ref)
     del config["track"]
@@ -1126,7 +1119,7 @@ def test_overwrite_rogue_tag_multiple_remotes(cli, tmpdir, datafiles):
         "kind": "import",
         "sources": [config],
     }
-    _yaml.roundtrip_dump(element, element_path)
+    generate_element(project, "target.bst", element)
 
     result = cli.run(project=project, args=["build", "target.bst"])
     result.assert_success()
diff --git a/tests/sources/no_fetch_cached.py b/tests/sources/no_fetch_cached.py
index 1ee3dd7bd..4984f5326 100644
--- a/tests/sources/no_fetch_cached.py
+++ b/tests/sources/no_fetch_cached.py
@@ -4,10 +4,9 @@
 import os
 import pytest
 
-from buildstream import _yaml
-
 from buildstream.testing import cli  # pylint: disable=unused-import
 from buildstream.testing import create_repo
+from buildstream.testing import generate_element
 from buildstream.testing._utils.site import HAVE_GIT
 
 DATA_DIR = os.path.join(os.path.dirname(os.path.realpath(__file__)), "no-fetch-cached")
@@ -28,7 +27,7 @@ def test_no_fetch_cached(cli, tmpdir, datafiles):
 
     # Write out test target with a cached and a non-cached source
     element = {"kind": "import", "sources": [repo.source_config(ref=ref), {"kind": "always_cached"}]}
-    _yaml.roundtrip_dump(element, os.path.join(project, "target.bst"))
+    generate_element(project, "target.bst", element)
 
     # Test fetch of target with a cached and a non-cached source
     result = cli.run(project=project, args=["source", "fetch", "target.bst"])
diff --git a/tests/sources/pip.py b/tests/sources/pip.py
index 7020f19c2..cfe20438a 100644
--- a/tests/sources/pip.py
+++ b/tests/sources/pip.py
@@ -4,19 +4,13 @@
 import os
 import pytest
 
-from buildstream import _yaml
 from buildstream.exceptions import ErrorDomain
 from buildstream.plugins.sources.pip import _match_package_name
-from buildstream.testing import cli  # pylint: disable=unused-import
+from buildstream.testing import cli, ErrorDomain, generate_project  # pylint: disable=unused-import
 
 DATA_DIR = os.path.join(os.path.dirname(os.path.realpath(__file__)), "pip",)
 
 
-def generate_project(project_dir):
-    project_file = os.path.join(project_dir, "project.conf")
-    _yaml.roundtrip_dump({"name": "foo"}, project_file)
-
-
 # Test that without ref, consistency is set appropriately.
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "no-ref"))
 def test_no_ref(cli, datafiles):
diff --git a/tests/sources/previous_source_access.py b/tests/sources/previous_source_access.py
index fadf6710c..3c95d77e2 100644
--- a/tests/sources/previous_source_access.py
+++ b/tests/sources/previous_source_access.py
@@ -4,7 +4,7 @@
 import os
 import pytest
 
-from buildstream import _yaml
+from buildstream.testing import generate_project, load_yaml
 from buildstream.testing import cli  # pylint: disable=unused-import
 
 DATA_DIR = os.path.join(os.path.dirname(os.path.realpath(__file__)), "previous_source_access")
@@ -20,10 +20,10 @@ def test_custom_transform_source(cli, datafiles):
 
     # Set the project_dir alias in project.conf to the path to the tested project
     project_config_path = os.path.join(project, "project.conf")
-    project_config = _yaml.load(project_config_path)
+    project_config = load_yaml(project_config_path)
     aliases = project_config.get_mapping("aliases")
     aliases["project_dir"] = "file://{}".format(project)
-    _yaml.roundtrip_dump(project_config, project_config_path)
+    generate_project(project, project_config)
 
     # Ensure we can track
     result = cli.run(project=project, args=["source", "track", "target.bst"])
diff --git a/tests/sources/remote.py b/tests/sources/remote.py
index 00a7687b3..d546c6131 100644
--- a/tests/sources/remote.py
+++ b/tests/sources/remote.py
@@ -6,28 +6,18 @@ import stat
 import pytest
 
 from buildstream.testing import ErrorDomain
-from buildstream import _yaml
+from buildstream.testing import generate_project
 from buildstream.testing import cli  # pylint: disable=unused-import
 from tests.testutils.file_server import create_file_server
 
 DATA_DIR = os.path.join(os.path.dirname(os.path.realpath(__file__)), "remote",)
 
 
-def generate_project(project_dir, tmpdir):
-    project_file = os.path.join(project_dir, "project.conf")
-    _yaml.roundtrip_dump({"name": "foo", "aliases": {"tmpdir": "file:///" + str(tmpdir)}}, project_file)
-
-
-def generate_project_file_server(server, project_dir):
-    project_file = os.path.join(project_dir, "project.conf")
-    _yaml.roundtrip_dump({"name": "foo", "aliases": {"tmpdir": server.base_url()}}, project_file)
-
-
 # Test that without ref, consistency is set appropriately.
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "no-ref"))
 def test_no_ref(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, {"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
     assert cli.get_element_state(project, "target.bst") == "no reference"
 
 
@@ -36,7 +26,7 @@ def test_no_ref(cli, tmpdir, datafiles):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "missing-file"))
 def test_missing_file(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, {"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
 
     # Try to fetch it
     result = cli.run(project=project, args=["source", "fetch", "target.bst"])
@@ -48,7 +38,7 @@ def test_missing_file(cli, tmpdir, datafiles):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "path-in-filename"))
 def test_path_in_filename(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, {"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
 
     # Try to fetch it
     result = cli.run(project=project, args=["source", "fetch", "target.bst"])
@@ -60,7 +50,8 @@ def test_path_in_filename(cli, tmpdir, datafiles):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "single-file"))
 def test_simple_file_build(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, {"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
+
     checkoutdir = os.path.join(str(tmpdir), "checkout")
 
     # Try to fetch it
@@ -87,7 +78,8 @@ def test_simple_file_build(cli, tmpdir, datafiles):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "single-file-custom-name"))
 def test_simple_file_custom_name_build(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, {"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
+
     checkoutdir = os.path.join(str(tmpdir), "checkout")
 
     # Try to fetch it
@@ -109,7 +101,8 @@ def test_unique_key(cli, tmpdir, datafiles):
     to generating a cache key for the source.
     """
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, {"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
+
     states = cli.get_element_states(project, ["target.bst", "target-custom.bst", "target-custom-executable.bst"])
     assert states["target.bst"] == "fetch needed"
     assert states["target-custom.bst"] == "fetch needed"
@@ -118,7 +111,7 @@ def test_unique_key(cli, tmpdir, datafiles):
     # Try to fetch it
     cli.run(project=project, args=["source", "fetch", "target.bst"])
 
-    # We should download the file only once
+    # We should download_yaml the file only once
     states = cli.get_element_states(project, ["target.bst", "target-custom.bst", "target-custom-executable.bst"])
     assert states["target.bst"] == "buildable"
     assert states["target-custom.bst"] == "buildable"
@@ -137,7 +130,8 @@ def test_executable(cli, tmpdir, datafiles):
     """This test confirms that the 'ecxecutable' parameter is honoured.
     """
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, {"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
+
     checkoutdir = os.path.join(str(tmpdir), "checkout")
     assert cli.get_element_state(project, "target-custom-executable.bst") == "fetch needed"
     # Try to fetch it
@@ -167,7 +161,7 @@ def test_use_netrc(cli, datafiles, server_type, tmpdir):
 
     with create_file_server(server_type) as server:
         server.add_user("testuser", "12345", project)
-        generate_project_file_server(server, project)
+        generate_project(project, {"aliases": {"tmpdir": server.base_url()}})
 
         server.start()
 
diff --git a/tests/sources/tar.py b/tests/sources/tar.py
index d35cc2964..8ac627492 100644
--- a/tests/sources/tar.py
+++ b/tests/sources/tar.py
@@ -11,8 +11,8 @@ import urllib.parse
 import pytest
 
 from buildstream import utils
-from buildstream import _yaml
 from buildstream.exceptions import ErrorDomain
+from buildstream.testing import generate_project, generate_element
 from buildstream.testing import cli  # pylint: disable=unused-import
 from buildstream.testing._utils.site import HAVE_LZIP
 from tests.testutils.file_server import create_file_server
@@ -41,21 +41,11 @@ def _assemble_tar_lz(workingdir, srcdir, dstfile):
     os.chdir(old_dir)
 
 
-def generate_project(project_dir, tmpdir):
-    project_file = os.path.join(project_dir, "project.conf")
-    _yaml.roundtrip_dump({"name": "foo", "aliases": {"tmpdir": "file:///" + str(tmpdir)}}, project_file)
-
-
-def generate_project_file_server(base_url, project_dir):
-    project_file = os.path.join(project_dir, "project.conf")
-    _yaml.roundtrip_dump({"name": "foo", "aliases": {"tmpdir": base_url}}, project_file)
-
-
 # Test that without ref, consistency is set appropriately.
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "no-ref"))
 def test_no_ref(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
     assert cli.get_element_state(project, "target.bst") == "no reference"
 
 
@@ -63,7 +53,7 @@ def test_no_ref(cli, tmpdir, datafiles):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "fetch"))
 def test_fetch_bad_url(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
 
     # Try to fetch it
     result = cli.run(project=project, args=["source", "fetch", "target.bst"])
@@ -76,7 +66,7 @@ def test_fetch_bad_url(cli, tmpdir, datafiles):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "fetch"))
 def test_fetch_bad_ref(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
 
     # Create a local tar
     src_tar = os.path.join(str(tmpdir), "a.tar.gz")
@@ -92,7 +82,7 @@ def test_fetch_bad_ref(cli, tmpdir, datafiles):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "fetch"))
 def test_track_warning(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
 
     # Create a local tar
     src_tar = os.path.join(str(tmpdir), "a.tar.gz")
@@ -109,7 +99,7 @@ def test_track_warning(cli, tmpdir, datafiles):
 @pytest.mark.parametrize("srcdir", ["a", "./a"])
 def test_stage_default_basedir(cli, tmpdir, datafiles, srcdir):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
     checkoutdir = os.path.join(str(tmpdir), "checkout")
 
     # Create a local tar
@@ -138,7 +128,7 @@ def test_stage_default_basedir(cli, tmpdir, datafiles, srcdir):
 @pytest.mark.parametrize("srcdir", ["a", "./a"])
 def test_stage_no_basedir(cli, tmpdir, datafiles, srcdir):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
     checkoutdir = os.path.join(str(tmpdir), "checkout")
 
     # Create a local tar
@@ -167,7 +157,7 @@ def test_stage_no_basedir(cli, tmpdir, datafiles, srcdir):
 @pytest.mark.parametrize("srcdir", ["a", "./a"])
 def test_stage_explicit_basedir(cli, tmpdir, datafiles, srcdir):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
     checkoutdir = os.path.join(str(tmpdir), "checkout")
 
     # Create a local tar
@@ -196,7 +186,7 @@ def test_stage_explicit_basedir(cli, tmpdir, datafiles, srcdir):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "contains-links"))
 def test_stage_contains_links(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
     checkoutdir = os.path.join(str(tmpdir), "checkout")
 
     # Create a local tar
@@ -232,7 +222,7 @@ def test_stage_contains_links(cli, tmpdir, datafiles):
 @pytest.mark.parametrize("srcdir", ["a", "./a"])
 def test_stage_default_basedir_lzip(cli, tmpdir, datafiles, srcdir):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
     checkoutdir = os.path.join(str(tmpdir), "checkout")
 
     # Create a local tar
@@ -265,17 +255,17 @@ def test_stage_default_basedir_lzip(cli, tmpdir, datafiles, srcdir):
 def test_read_only_dir(cli, tmpdir, datafiles, tar_name, base_dir):
     try:
         project = str(datafiles)
-        generate_project(project, tmpdir)
+        generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
 
-        bst_path = os.path.join(project, "target.bst")
         tar_file = "{}.tar.gz".format(tar_name)
 
-        _yaml.roundtrip_dump(
+        generate_element(
+            project,
+            "target.bst",
             {
                 "kind": "import",
                 "sources": [{"kind": "tar", "url": "tmpdir:/{}".format(tar_file), "ref": "foo", "base-dir": base_dir}],
             },
-            bst_path,
         )
 
         # Get the tarball in tests/sources/tar/read-only/content
@@ -326,7 +316,7 @@ def test_use_netrc(cli, datafiles, server_type, tmpdir):
 
     with create_file_server(server_type) as server:
         server.add_user("testuser", "12345", file_server_files)
-        generate_project_file_server(server.base_url(), project)
+        generate_project(project, config={"aliases": {"tmpdir": server.base_url()}})
 
         src_tar = os.path.join(file_server_files, "a.tar.gz")
         _assemble_tar(os.path.join(str(datafiles), "content"), "a", src_tar)
@@ -368,7 +358,7 @@ def test_netrc_already_specified_user(cli, datafiles, server_type, tmpdir):
         server.add_user("otheruser", "12345", file_server_files)
         parts = urllib.parse.urlsplit(server.base_url())
         base_url = urllib.parse.urlunsplit([parts[0], "otheruser@{}".format(parts[1]), *parts[2:]])
-        generate_project_file_server(base_url, project)
+        generate_project(project, config={"aliases": {"tmpdir": base_url}})
 
         src_tar = os.path.join(file_server_files, "a.tar.gz")
         _assemble_tar(os.path.join(str(datafiles), "content"), "a", src_tar)
@@ -385,7 +375,7 @@ def test_netrc_already_specified_user(cli, datafiles, server_type, tmpdir):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "fetch"))
 def test_homeless_environment(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
 
     # Create a local tar
     src_tar = os.path.join(str(tmpdir), "a.tar.gz")
@@ -407,7 +397,7 @@ def test_out_of_basedir_hardlinks(cli, tmpdir, datafiles):
         return member
 
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
     checkoutdir = os.path.join(str(tmpdir), "checkout")
 
     # Create a tarball with an odd hardlink
@@ -445,7 +435,7 @@ def test_out_of_basedir_hardlinks(cli, tmpdir, datafiles):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "out-of-basedir-hardlinks"))
 def test_malicious_out_of_basedir_hardlinks(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
 
     # Create a maliciously-hardlinked tarball
     def ensure_link(member):
diff --git a/tests/sources/zip.py b/tests/sources/zip.py
index 7c47058b5..201271fe0 100644
--- a/tests/sources/zip.py
+++ b/tests/sources/zip.py
@@ -6,8 +6,8 @@ import zipfile
 
 import pytest
 
-from buildstream import _yaml
 from buildstream.exceptions import ErrorDomain
+from buildstream.testing import generate_project
 from buildstream.testing import cli  # pylint: disable=unused-import
 from tests.testutils.file_server import create_file_server
 from . import list_dir_contents
@@ -27,21 +27,11 @@ def _assemble_zip(workingdir, dstfile):
     os.chdir(old_dir)
 
 
-def generate_project(project_dir, tmpdir):
-    project_file = os.path.join(project_dir, "project.conf")
-    _yaml.roundtrip_dump({"name": "foo", "aliases": {"tmpdir": "file:///" + str(tmpdir)}}, project_file)
-
-
-def generate_project_file_server(server, project_dir):
-    project_file = os.path.join(project_dir, "project.conf")
-    _yaml.roundtrip_dump({"name": "foo", "aliases": {"tmpdir": server.base_url()}}, project_file)
-
-
 # Test that without ref, consistency is set appropriately.
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "no-ref"))
 def test_no_ref(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
     assert cli.get_element_state(project, "target.bst") == "no reference"
 
 
@@ -49,7 +39,7 @@ def test_no_ref(cli, tmpdir, datafiles):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "fetch"))
 def test_fetch_bad_url(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
 
     # Try to fetch it
     result = cli.run(project=project, args=["source", "fetch", "target.bst"])
@@ -62,7 +52,7 @@ def test_fetch_bad_url(cli, tmpdir, datafiles):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "fetch"))
 def test_fetch_bad_ref(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
 
     # Create a local tar
     src_zip = os.path.join(str(tmpdir), "a.zip")
@@ -78,7 +68,7 @@ def test_fetch_bad_ref(cli, tmpdir, datafiles):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "fetch"))
 def test_track_warning(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
 
     # Create a local tar
     src_zip = os.path.join(str(tmpdir), "a.zip")
@@ -94,7 +84,7 @@ def test_track_warning(cli, tmpdir, datafiles):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "fetch"))
 def test_stage_default_basedir(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
     checkoutdir = os.path.join(str(tmpdir), "checkout")
 
     # Create a local tar
@@ -122,7 +112,7 @@ def test_stage_default_basedir(cli, tmpdir, datafiles):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "no-basedir"))
 def test_stage_no_basedir(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
     checkoutdir = os.path.join(str(tmpdir), "checkout")
 
     # Create a local tar
@@ -150,7 +140,7 @@ def test_stage_no_basedir(cli, tmpdir, datafiles):
 @pytest.mark.datafiles(os.path.join(DATA_DIR, "explicit-basedir"))
 def test_stage_explicit_basedir(cli, tmpdir, datafiles):
     project = str(datafiles)
-    generate_project(project, tmpdir)
+    generate_project(project, config={"aliases": {"tmpdir": "file:///" + str(tmpdir)}})
     checkoutdir = os.path.join(str(tmpdir), "checkout")
 
     # Create a local tar
@@ -193,7 +183,7 @@ def test_use_netrc(cli, datafiles, server_type, tmpdir):
 
     with create_file_server(server_type) as server:
         server.add_user("testuser", "12345", file_server_files)
-        generate_project_file_server(server, project)
+        generate_project(project, config={"aliases": {"tmpdir": server.base_url()}})
 
         src_zip = os.path.join(file_server_files, "a.zip")
         _assemble_zip(os.path.join(str(datafiles), "content"), src_zip)
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