Make pip_library zip safety end-to-end tests self-contained (#256)

The end-to-end tests that check whether `pip_library` correctly applies
the `py:zip-unsafe` label to a zip-unsafe target depend on two
third-party Python modules, PyYAML and grpcio. The pre-built wheels on
PyPI are architecture-specific, so their versions have to be kept in
line with ones for which pre-built wheels are available on PyPI
(otherwise pip will take > 10 minutes and a lot of resources to build
them from source); even when a pre-built wheel is available for the
SOABI in question, the download is disproportionately large for such a
simple test (7-12MB for grpcio, depending on the SOABI).

Replace the `pip_library` zip safety tests with a single, fully
self-contained e2e test that occurs within an e2e-specific Please repo,
requiring no downloads from PyPI.

Author: chrisnovakovic

.plzconfig

@@ -1,5 +1,5 @@
 [Please]
-Version = >=17.12.2
+Version = >=17.19.1
 
 [Build]
 hashcheckers = sha256
@@ -18,6 +18,7 @@ Target = //plugins:shell
 
 [Plugin "e2e"]
 Target = //plugins:e2e
+DefaultPlugin = //test:python-rules
 
 [PluginDefinition]
 name = python

BUILD

@@ -11,3 +11,12 @@ remote_file(
     url = f"https://get.please.build/{CONFIG.OS}_{CONFIG.ARCH}/{v}/please_{v}",
     visibility = ["PUBLIC"],
 )
+
+export_file(
+    name = "plzconfig",
+    src = ".plzconfig",
+    test_only = True,
+    visibility = [
+        "//test:python-rules",
+    ],
+)

plugins/BUILD

@@ -11,5 +11,5 @@ plugin_repo(
 plugin_repo(
     name = "e2e",
     plugin = "plugin-integration-testing",
-    revision = "v1.0.3",
+    revision = "v1.1.0",
 )

test/BUILD

@@ -17,6 +17,20 @@ package(
     },
 )
 
+e2e_test_plugin(
+    name = "python-rules",
+    srcs = [
+        "//build_defs:archs",
+        "//build_defs:python",
+        "//build_defs:version",
+        "//tools:please_pex",
+        "//:plzconfig",
+    ],
+    visibility = [
+        "//test/...",
+    ],
+)
+
 python_binary(
     name = "strip_source",
     main = "strip_source.py",
@@ -132,18 +146,19 @@ python_test(
     deps = ["//third_party/python:cx_oracle"],
 )
 
-plz_e2e_test(
-    name = "correct_labels_on_pip_libary_non_zip_safe",
-    cmd = "plz query print -f labels //third_party/python:pyyaml",
-    expected_output = "expected_labels_on_pyyaml.txt",
-    deps = ["//third_party/python:pyyaml"],
-)
-
-plz_e2e_test(
-    name = "correct_labels_on_pip_libary_zip_safe",
-    cmd = "plz query print -f labels //third_party/python:grpcio",
-    expected_output = "expected_labels_on_grpcio.txt",
-    deps = ["//third_party/python:grpcio"],
+plugin_e2e_test(
+    name = "pip_libary_zip_safe_label_test",
+    repo = "zip_safe_label_repo",
+    test_cmd = [
+        "plz query print -f labels //third_party/python:safe > safe",
+        "plz query print -f labels //third_party/python:safe_implicit > safe_implicit",
+        "plz query print -f labels //third_party/python:unsafe > unsafe",
+    ],
+    expected_output = {
+        "safe": "py\npip:safe==1.0.0",
+        "safe_implicit": "py\npip:safe_implicit==1.0.0",
+        "unsafe": "py\npip:unsafe==1.0.0\npy:zip-unsafe",
+    },
 )
 
 # Test that python_wheel targets can have name_scheme as a list or a string

test/expected_labels_on_grpcio.txt

@@ -0,0 +1,2 @@
+[Plugin "python"]
+Target = //plugins:python

test/expected_labels_on_pyyaml.txt

@@ -0,0 +1,4 @@
+plugin_repo(
+    name = "python",
+    revision = "e2e",
+)

test/zip_safe_label_repo/.plzconfig

@@ -0,0 +1,33 @@
+subinclude("///python//build_defs:python")
+
+package(
+    # The pip_library targets below aren't real Python modules, and don't need to be downloaded in
+    # order for this test to run - make sure we don't accidentally look for them on PyPI.
+    python = {
+        "default_pip_repo": "https://nonexistent.example",
+        "use_pypi": False,
+    },
+)
+
+# This target is explicitly zip-safe:
+pip_library(
+    name = "safe",
+    licences = ["MIT"],
+    version = "1.0.0",
+    zip_safe = True,
+)
+
+# This target is implicitly zip-safe, because it specifies no value for zip_safe:
+pip_library(
+    name = "safe_implicit",
+    licences = ["MIT"],
+    version = "1.0.0",
+)
+
+# This target is explicitly zip-unsafe:
+pip_library(
+    name = "unsafe",
+    licences = ["MIT"],
+    version = "1.0.0",
+    zip_safe = False,
+)