code: def test_partial_env():
      assert PartialEnv(a=1, b=2) == {"a": 1, "b": 2, "c": 3}
      assert PartialEnv(a=1) == {"a": 1, "b": 2, "c": 3}
      assert PartialEnv(a=1, b=2) == {"a": 1, "b": 2}
      assert PartialEnv(a=1, b=2) != {"b": 2, "c": 3}
      assert PartialEnv(a=1, b=2) != {"a": 1, "c": 3}
  
imports: import subprocess
  import pytest
  from archery.testing import PartialEnv, assert_subprocess_calls
label_desc: Use image node_id 1 for calling a global function with example usage: test_partial_env() without return types