Handle doubleton mutant filter in command line

mutmut/__main__.py

@@ -962,6 +962,13 @@ def _run(mutant_names: Union[tuple, list], max_children: Union[None, int]):
     # TODO: we should be able to get information on which tests killed mutants, which means we can get a list of tests and how many mutants each test kills. Those that kill zero mutants are redundant!
     os.environ['MUTANT_UNDER_TEST'] = 'mutant_generation'
     ensure_config_loaded()
+    if isinstance(mutant_names, tuple):
+        bits = []
+        for item in mutant_names:
+            bits.extend(item.split(' '))
+
+        if len(bits) > len(mutant_names):
+            mutant_names = tuple(bits)
 
     if max_children is None:
         max_children = os.cpu_count() or 4

tests/e2e/test_e2e_result_filter.py

@@ -0,0 +1,126 @@
+import json
+import os
+import shutil
+from contextlib import contextmanager
+from pathlib import Path
+from typing import Any
+
+import mutmut
+from mutmut.__main__ import SourceFileMutationData, _run, ensure_config_loaded, walk_source_files
+
+@contextmanager
+def change_cwd(path):
+    old_cwd = Path(Path.cwd()).resolve()
+    os.chdir(path)
+    try:
+        yield
+    finally:
+        os.chdir(old_cwd)
+
+
+def read_all_stats_for_project(project_path: Path) -> dict[str, dict]:
+    """Create a single dict from all mutant results in *.meta files"""
+    with change_cwd(project_path):
+        ensure_config_loaded()
+
+        stats = {}
+        for p in walk_source_files():
+            if mutmut.config.should_ignore_for_mutation(p):  # type: ignore
+                continue
+            data = SourceFileMutationData(path=p)
+            data.load()
+            stats[str(data.meta_path)] = data.exit_code_by_key
+
+        return stats
+
+
+def read_json_file(path: Path):
+    with open(path, 'r') as file:
+        return json.load(file)
+
+
+def write_json_file(path: Path, data: Any):
+    with open(path, 'w') as file:
+        json.dump(data, file, indent=2)
+
+
+def asserts_handled_mutant_spec(project: str, filter_mutants: str):
+    """Runs mutmut on this project and verifies that it was able to handle the supplied mutant spec."""
+    project_path = Path("..").parent / "e2e_projects" / project
+
+    mutants_path = project_path / "mutants"
+    shutil.rmtree(mutants_path, ignore_errors=True)
+
+    # mutmut run
+    no_exception = True
+    exception_type = None
+    try:
+        with change_cwd(project_path):
+            mut_names = tuple([filter_mutants])
+            _run(mut_names, None)
+    except Exception as e:
+        no_exception = False
+        exception_type = e
+
+    assert no_exception, str(exception_type)
+
+
+def asserts_handled_mutant_spec_extra(project: str, tuple_first: str, filter_mutants: str):
+    """Runs mutmut on this project and verifies that it was able to handle the supplied mutant spec."""
+    project_path = Path("..").parent / "e2e_projects" / project
+
+    mutants_path = project_path / "mutants"
+    shutil.rmtree(mutants_path, ignore_errors=True)
+
+    # Work out a lower bound on the number of mutants that _should_ have run
+    min_count = 2 + tuple_first.count(' ') + filter_mutants.count(' ')
+
+    # mutmut run
+    no_exception = True
+    exception_type = None
+    try:
+        with change_cwd(project_path):
+            mut_names = tuple([tuple_first, filter_mutants])
+            _run(mut_names, None)
+    except Exception as e:
+        no_exception = False
+        exception_type = e
+
+    assert no_exception, str(exception_type)
+
+    results = read_all_stats_for_project(project_path)
+    actual_count = 0
+    for item in results:
+        matches = [1 for v in list(results[item].values()) if isinstance(v, int) and 33 != v]
+        actual_count += sum(matches)
+
+    assert actual_count >= min_count,\
+        f"Test config expected at least {min_count} mutants run, only {actual_count} mutant was/were run"
+
+
+def test_config_result_filter_singleton_mutant_explicit():
+    mutmut._reset_globals()
+    asserts_handled_mutant_spec("config", "config_pkg.math.x_add__mutmut_1")
+
+
+def test_config_result_filter_singleton_mutant_wildcard():
+    mutmut._reset_globals()
+    asserts_handled_mutant_spec("config", "config_pkg.math.x_call_depth_two__mutmut_?")
+
+
+def test_config_result_filter_doubleton_mutant_explicit():
+    mutmut._reset_globals()
+    asserts_handled_mutant_spec("config", "config_pkg.math.x_call_depth_two__mutmut_1 config_pkg.math.x_add__mutmut_1")
+
+
+def test_config_result_filter_doubleton_mutant_wildcard():
+    mutmut._reset_globals()
+    asserts_handled_mutant_spec("config", "config_pkg.math.x_call_depth_two__mutmut_? config_pkg.math.x_add__mutmut_?")
+
+
+def test_config_result_filter_tuple_plus_doubleton():
+    mutmut._reset_globals()
+    asserts_handled_mutant_spec_extra(
+        'config',
+        'config_pkg.x_hello__mutmut_1', 'config_pkg.math.x_call_depth_two__mutmut_? config_pkg.math.x_add__mutmut_?'
+    )