tests: adds first party dependencies to the container test, add note about usage

py/tests/containers/BUILD.bazel

@@ -6,10 +6,21 @@ py_binary(
     name = "main_bin",
     srcs = ["__main__.py"],
     deps = [
+        "//py/tests/containers/branding",
+        "//py/tests/internal-deps/adder",
         "@pypi_colorama//:pkg",
     ],
 )
 
+# py3_image container support reverts us back to the rules_python way of invoking the binary,
+# (as really there is a py_binary in the py3_image).
+# This test ensures that rules_py can still run in that mode, but there are a few notable exceptions:
+#   * There is no longer a virtual env to run in
+#   * The rules_py launcher isn't invoked
+#   * There is no pip
+#   * Dependencies that were consumed via wheel targets are lost
+# Perhaps rules_container can provide a suitable alternative here, or rules_py provides a thin wrapper around the
+# rules_docker container_image that produces the expected output, but it would be limited in terms of customisation.
 py3_image(
     name = "py_image",
     srcs = ["__main__.py"],

py/tests/containers/__main__.py

@@ -1,4 +1,7 @@
 from colorama import Fore, Style
 
+from branding import get_branding
+from adder.add import add
+
 if __name__ == "__main__":
-    print(f"{Fore.GREEN}Hello rules_py{Style.RESET_ALL}")
+    print(f"{Fore.GREEN}Hello {get_branding()} - {add(3, .14)}{Style.RESET_ALL}")

py/tests/containers/branding/BUILD.bazel

@@ -0,0 +1,8 @@
+load("//py:defs.bzl", "py_library")
+
+py_library(
+    name = "branding",
+    srcs = ["__init__.py"],
+    imports = [".."],
+    visibility = ["//py/tests/containers:__pkg__"],
+)

py/tests/containers/branding/__init__.py

@@ -0,0 +1,2 @@
+def get_branding():
+    return "rules_py"

py/tests/containers/py_image_test.yaml

@@ -11,4 +11,4 @@ commandTests:
     command: /usr/bin/python
     args:
       - /app/py/tests/containers/py_image.binary
-    expectedOutput: ["Hello rules_py"]
+    expectedOutput: ["Hello rules_py - 3.14"]

py/tests/internal-deps/BUILD.bazel

@@ -8,16 +8,6 @@ rules_py_py_library(
     ],
 )
 
-rules_py_py_library(
-    name = "add",
-    srcs = [
-        "add.py",
-    ],
-    deps = [
-        ":init",
-    ],
-)
-
 rules_py_py_library(
     name = "sub",
     srcs = [
@@ -44,9 +34,9 @@ py_binary(
         "__main__.py",
     ],
     deps = [
-        ":add",
         ":pi",
         ":sub",
+        "//py/tests/internal-deps/adder",
     ],
 )
 
@@ -56,8 +46,8 @@ py_test(
         "__main__.py",
     ],
     deps = [
-        ":add",
         ":pi",
         ":sub",
+        "//py/tests/internal-deps/adder",
     ],
 )

py/tests/internal-deps/__main__.py

@@ -1,4 +1,4 @@
-from add import add
+from adder.add import add
 from sub import sub
 from pi import format_pi
 

py/tests/internal-deps/adder/BUILD.bazel

@@ -0,0 +1,16 @@
+load("//py:defs.bzl", "py_library")
+
+py_library(
+    name = "adder",
+    srcs = [
+        "__init__.py",
+        "add.py",
+    ],
+    imports = [".."],
+    # This library contributes to the container test, testing we can pull in and use a library from another
+    # package in the repo.
+    visibility = [
+        "//py/tests/containers:__pkg__",
+        "//py/tests/internal-deps:__pkg__",
+    ],
+)