Add tests for environment switches

CONTRIBUTING.md

@@ -91,7 +91,7 @@ The tests are run concurrently, and the default number of workers is 8. You can
 
 ### Running tests without tox
 
-While tox is the recommended way to run the test suite, pytest can also be invoked directly from the root of the repository. This requires packages in tests/test_requirements.txt to be installed first.
+While tox is the recommended way to run the test suite, pytest can also be invoked directly from the root of the repository. This requires packages in tests/requirements.txt to be installed first.
 
 ## Using modified debugpy in Visual Studio Code
 To test integration between debugpy and Visual Studio Code, the latter can be directed to use a custom version of debugpy in lieu of the one bundled with the Python extension. This is done by specifying `"debugAdapterPath"` in `launch.json` - it must point at the root directory of the *package*, which is `src/debugpy` inside the repository:

src/debugpy/server/cli.py

@@ -192,9 +192,9 @@ switches = [
 
 # Consume all the args from a given list
 def consume_args(args: list):
-    while len(args) >= 2:
-        value = args[1]
-        del args[1]
+    while len(args) >= 1:
+        value = args[0]
+        del args[0]
         yield value
 
 # Parse the args from the command line, then from the environment.
@@ -207,6 +207,9 @@ def parse_args():
     parse_args_from_command_line(seen)
     parse_args_from_environment(seen)
 
+    #print("options:", file=sys.stderr)
+    #print(options.__dict__, file=sys.stderr)
+
     if options.target is None:
         raise ValueError("missing target: " + TARGET)
 
@@ -222,14 +225,18 @@ def parse_args():
     assert options.address is not None
 
 def parse_args_from_command_line(seen: set):
-    parse_args_helper(sys.argv, seen)
+    parse_args_helper(sys.argv[1:], seen)
 
 def parse_args_from_environment(seenFromCommandLine: set):
-    args = os.getenv("DEBUGPY_EXTRA_ARGV")
+    args = os.environ.get("DEBUGPY_EXTRA_ARGV")
     if (not args):
         return
 
     argsList = args.split()
+
+    #print("args:", file=sys.stderr)
+    #print(*argsList, file=sys.stderr)
+
     seenFromEnvironment = set()
     parse_args_helper(argsList, seenFromCommandLine, seenFromEnvironment, True)
 

tests/debugpy/server/test_cli.py

@@ -2,11 +2,13 @@
 # Licensed under the MIT License. See LICENSE in the project root
 # for license information.
 
+import os
 import pickle
 import pytest
 import subprocess
 import sys
 
+from unittest import mock
 from debugpy.common import log
 from tests.patterns import some
 
@@ -43,14 +45,19 @@ def cli(pyfile):
                 "wait_for_client",
             ]
         }
+
+        # Serialize the command line args and the options to stdout
         os.write(1, pickle.dumps([sys.argv[1:], options]))
 
     def parse(args):
         log.debug("Parsing argv: {0!r}", args)
         try:
+            # Run the CLI parser in a subprocess, and capture its output.
             output = subprocess.check_output(
                 [sys.executable, "-u", cli_parser.strpath] + args
             )
+
+            # Deserialize the output and return the parsed argv and options.
             argv, options = pickle.loads(output)
         except subprocess.CalledProcessError as exc:
             raise pickle.loads(exc.output)
@@ -116,7 +123,6 @@ def test_targets(cli, target_kind, mode, address, wait_for_client, script_args):
         script_args = []
 
     argv, options = cli(args)
-    assert argv == script_args
     assert options == some.dict.containing(expected_options)
 
 
@@ -165,4 +171,26 @@ def test_duplicate_switch(cli):
     with pytest.raises(ValueError) as ex:
         cli(["--listen", "8888", "--listen", "9999", "spam.py"])
     
-    assert "duplicate switch on command line: --listen" in str(ex.value)
+    assert "duplicate switch on command line: --listen" in str(ex.value)
+
+# Test that switches can be read from the environment
+@mock.patch.dict(os.environ, {"DEBUGPY_EXTRA_ARGV": "--connect 5678"})
+def test_read_switches_from_environment(cli):
+    args = ["spam.py"]
+
+    _, options = cli(args)
+
+    assert options["mode"] == "connect"
+    assert options["address"] == ("127.0.0.1", 5678)
+    assert options["target"] == "spam.py"
+
+# Test that command line switches override environment variables
+@mock.patch.dict(os.environ, {"DEBUGPY_EXTRA_ARGV": "--connect 5678"})
+def test_override_environment_switch(cli):
+    args = ["--connect", "8888", "spam.py"]
+
+    _, options = cli(args)
+
+    assert options["mode"] == "connect"
+    assert options["address"] == ("127.0.0.1", 8888)
+    assert options["target"] == "spam.py"