add depset characterization tests

Author: aignas

tests/venv_site_packages_libs/BUILD.bazel

@@ -1,6 +1,11 @@
 load("//python:py_library.bzl", "py_library")
 load("//tests/support:py_reconfig.bzl", "py_reconfig_test")
 load("//tests/support:support.bzl", "SUPPORTS_BOOTSTRAP_SCRIPT")
+load(":depset_tests.bzl", "depset_test_suite")
+
+depset_test_suite(
+    name = "depset_tests",
+)
 
 py_library(
     name = "user_lib",

tests/venv_site_packages_libs/depset_tests.bzl

@@ -0,0 +1,50 @@
+""
+
+load("@rules_testing//lib:test_suite.bzl", "test_suite")
+
+_tests = []
+
+def _test_simple(env):
+    c1 = depset(
+        ["c1"],
+        order = "topological",
+    )
+    c2 = depset(
+        ["c2"],
+        order = "topological",
+    )
+    b = depset(
+        ["b"],
+        transitive = [c1],
+        order = "topological",
+    )
+    a1 = depset(
+        ["A"],
+        transitive = [c2, b],
+        order = "topological",
+    )
+    a2 = depset(
+        ["A"],
+        transitive = [b, c2],
+        order = "topological",
+    )
+
+    got1 = a1.to_list()
+    got2 = a2.to_list()
+
+    env.expect.that_collection(got1).contains_exactly(
+        ["A", "c2", "b", "c1"],
+    ).in_order()
+    env.expect.that_collection(got2).contains_exactly(
+        ["A", "b", "c1", "c2"],
+    ).in_order()
+
+_tests.append(_test_simple)
+
+def depset_test_suite(name):
+    """Create the test suite.
+
+    Args:
+        name: the name of the test suite
+    """
+    test_suite(name = name, basic_tests = _tests)