test: add EnvSpec/Env unit tests, raising coverage to 84%

Adds unit tests for EnvSpec (names, __str__, identity_attributes,
source_path_attributes, __hash__/__eq__, dict-key usability) and the pure
Env methods (decorate_shellcmd, record_hash, report_software). The hash tests
guard the classmethod fix. Coverage rises from 64.86% to 83.78%, clearing the
fail-under=70 gate. Env.check/__post_init__/contains_executable stay uncovered
as they require a live `module` command.

Author: jiangyun-fun

tests/test_plugin.py

@@ -1,4 +1,6 @@
+import hashlib
 import os
+from types import SimpleNamespace
 from typing import Optional, Type
 from snakemake_interface_software_deployment_plugins import EnvBase, EnvSpecBase
 from snakemake_interface_software_deployment_plugins.tests import (
@@ -44,3 +46,95 @@ def get_settings(
     def get_test_cmd(self) -> str:
         # Return a command that should be executable without error in the environment
         return "somecmd"
+
+
+# ---------------------------------------------------------------------------
+# Unit tests for EnvSpec and the pure Env methods.
+#
+# These raise test coverage and guard the fix that made
+# identity_attributes / source_path_attributes classmethods (so that EnvSpec is
+# hashable and usable as a dict key, which the software-deployment manager
+# relies on for its specs_to_envs cache).
+# ---------------------------------------------------------------------------
+
+
+def _env_with_spec(spec):
+    """An Env-like object with only `.spec` set.
+
+    Env.__post_init__ runs check(), which needs the `module` command, so we
+    bypass construction and exercise only methods that depend on self.spec.
+    """
+    return SimpleNamespace(spec=spec)
+
+
+def _spec(*names):
+    """Construct an EnvSpec the way the directive factory does (with technical_init).
+
+    technical_init() is required before hashing/equality, because EnvSpecBase.__hash__
+    reads managed attributes (e.g. self.kind) that it sets.
+    """
+    spec = EnvSpec(*names)
+    spec.technical_init()
+    return spec
+
+
+def test_envspec_stores_names_as_tuple():
+    assert _spec("bwa", "samtools").names == ("bwa", "samtools")
+
+
+def test_envspec_str_is_comma_joined():
+    assert str(_spec("bwa", "samtools")) == "bwa,samtools"
+    assert str(_spec("bwa")) == "bwa"
+
+
+def test_identity_attributes_yields_names():
+    # classmethod: callable on the class itself
+    assert list(EnvSpec.identity_attributes()) == ["names"]
+
+
+def test_source_path_attributes_is_empty():
+    assert list(EnvSpec.source_path_attributes()) == []
+
+
+def test_envspec_hash_and_equality_use_names():
+    # Regression guard: __hash__ resolves through cls.identity_attributes(),
+    # which only works because identity_attributes is now a @classmethod.
+    a = _spec("bwa", "samtools")
+    b = _spec("bwa", "samtools")
+    c = _spec("bwa")
+    assert a == b
+    assert hash(a) == hash(b)
+    assert a != c
+    assert hash(a) != hash(c)
+
+
+def test_envspec_is_usable_as_dict_key():
+    # The original crash: hashing an envmodules spec raised TypeError, so it
+    # could not be used as a dict key (e.g. in specs_to_envs).
+    spec = _spec("bwa")
+    lookup = _spec("bwa")
+    assert {spec: "env"}[lookup] == "env"
+
+
+def test_env_decorate_shellcmd_loads_modules():
+    env = _env_with_spec(_spec("bwa", "samtools"))
+    assert Env.decorate_shellcmd(env, "echo hi") == (
+        "module purge && module load bwa samtools && echo hi"
+    )
+
+
+def test_env_decorate_shellcmd_quotes_unsafe_names():
+    env = _env_with_spec(_spec("name with space"))
+    assert "module load 'name with space'" in Env.decorate_shellcmd(env, "cmd")
+
+
+def test_env_record_hash_uses_names():
+    env = _env_with_spec(_spec("bwa", "samtools"))
+    h = hashlib.sha256()
+    Env.record_hash(env, h)
+    assert h.hexdigest() == hashlib.sha256(b"bwa,samtools").hexdigest()
+
+
+def test_env_report_software_is_empty():
+    env = _env_with_spec(_spec("bwa"))
+    assert list(Env.report_software(env)) == []