feat(P02): core/env.synthesize_local_env — local env synthesizer (REQ-330, backend-engineer)

---ci---
project: acdl
phase: 2
milestone: v1.28
status: execute
persona: backend-engineer
---
synthesize_local_env(contract_path, environment) reads a contract YAML and
produces a purely synthetic local env dict (account_id=000000000000
placeholder, region='local', local state_backend, local network) that
validates against schemas/environment.schema.json. Mirrors the shape of
core/environments/*.json + core/onboarding.py:generate_env_file() (shape
parity on the required env-binding keys). No cloud provisioning — purely
synthetic for nova apply --local. tests/test_local_env.py: 13 tests
(schema validation, region/account sentinels, env override, threshold
per-env, shape parity, missing-file default).

tests/test_local_env.py

@@ -0,0 +1,149 @@
+"""REQ-330 tests: core.env.synthesize_local_env — local env synthesizer.
+
+Verifies the synthesizer:
+  - reads a contract YAML and produces a local env dict
+  - the dict mirrors the shape of core/environments/*.json (validates
+    against schemas/environment.schema.json)
+  - region is "local" + account_id is the placeholder (no real AWS)
+  - the environment override wins over the contract's environment field
+  - mirrors core/onboarding.py:generate_env_file() shape (same required keys)
+"""
+
+from __future__ import annotations
+
+import json
+import sys
+from pathlib import Path
+
+import jsonschema
+import pytest
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+from core.env import synthesize_local_env
+
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+ENV_SCHEMA_PATH = REPO_ROOT / "schemas" / "environment.schema.json"
+
+
+@pytest.fixture
+def env_schema():
+    return json.loads(ENV_SCHEMA_PATH.read_text())
+
+
+@pytest.fixture
+def sample_contract(tmp_path):
+    """A minimal contract YAML for the synthesizer to read."""
+    contract = """
+id: msvc
+name: microservice
+environment: dev
+infrastructure:
+  microservice:
+    version: "1.0.0"
+    inputs:
+      image: nginx:latest
+"""
+    p = tmp_path / "contract.yml"
+    p.write_text(contract)
+    return p
+
+
+class TestSynthesizeLocalEnv:
+    def test_returns_dict_with_required_keys(self, sample_contract, env_schema):
+        env = synthesize_local_env(str(sample_contract))
+        assert isinstance(env, dict)
+        # The schema-required keys.
+        for key in (
+            "name", "account_id", "region", "state_backend",
+            "network", "runner_role_arn", "autonomy", "confidence_threshold",
+        ):
+            assert key in env, f"missing required key: {key}"
+
+    def test_validates_against_environment_schema(self, sample_contract, env_schema):
+        env = synthesize_local_env(str(sample_contract))
+        jsonschema.validate(env, env_schema)  # raises on invalid
+
+    def test_region_is_local(self, sample_contract):
+        env = synthesize_local_env(str(sample_contract))
+        assert env["region"] == "local", "region must be the local sentinel"
+
+    def test_account_id_is_placeholder(self, sample_contract):
+        env = synthesize_local_env(str(sample_contract))
+        assert env["account_id"] == "000000000000", (
+            "account_id must be the placeholder (no real AWS account)"
+        )
+
+    def test_state_backend_is_local(self, sample_contract):
+        env = synthesize_local_env(str(sample_contract))
+        sb = env["state_backend"]
+        assert sb["bucket"] == "local-tfstate"
+        assert sb["lock_table"] == "local-locks"
+
+    def test_uses_contract_environment_by_default(self, sample_contract):
+        env = synthesize_local_env(str(sample_contract))
+        assert env["name"] == "dev"  # the contract's environment field
+
+    def test_environment_override_wins(self, sample_contract):
+        env = synthesize_local_env(str(sample_contract), environment="qa")
+        assert env["name"] == "qa"
+        # qa threshold is 0.75 (per-env default)
+        assert env["confidence_threshold"] == 0.75
+
+    def test_confidence_threshold_per_env(self, sample_contract):
+        for env_name, expected in (("dev", 0.50), ("qa", 0.75), ("prod", 0.90), ("dr", 0.95)):
+            env = synthesize_local_env(str(sample_contract), environment=env_name)
+            assert env["confidence_threshold"] == expected, env_name
+
+    def test_autonomy_is_full(self, sample_contract):
+        env = synthesize_local_env(str(sample_contract))
+        assert env["autonomy"] == "full"  # local tier is autonomous
+
+    def test_no_real_aws_resources(self, sample_contract):
+        """The synthesizer must NOT reference real AWS resources — region
+        is 'local', the ARN uses the placeholder account, the bucket is local."""
+        env = synthesize_local_env(str(sample_contract))
+        assert "us-east-1" not in env["region"]
+        assert "000000000000" in env["runner_role_arn"]
+        assert "local" in env["state_backend"]["bucket"]
+
+    def test_mirrors_onboarding_env_file_shape(self, sample_contract, env_schema):
+        """The synthesized env has the same core shape as
+        core/onboarding.py:generate_env_file() output — both carry the
+        schema-required environment-binding keys. (generate_env_file adds
+        ownerId/billingTag for the onboarding request path; the synthesizer
+        is the local-tier counterpart and omits those — no consumer binding.)"""
+        from core.onboarding import generate_env_file
+        request = {
+            "consumerRepo": "acdl/consumer-a",
+            "requestedEnvironment": "dev",
+            "ownerId": "team-a",
+            "billingTag": "cc-a",
+        }
+        onboarded = generate_env_file(request)
+        # The synthesizer output validates against the env schema.
+        synth = synthesize_local_env(str(sample_contract))
+        jsonschema.validate(synth, env_schema)
+        # Both carry the schema-required environment-binding keys.
+        required = {
+            "name", "account_id", "region", "state_backend",
+            "network", "runner_role_arn", "autonomy", "confidence_threshold",
+        }
+        assert required <= set(onboarded.keys()), "onboarding output missing required keys"
+        assert required <= set(synth.keys()), "synthesizer output missing required keys"
+        # The synthesizer omits the onboarding-request-only keys.
+        assert "ownerId" not in synth
+        assert "billingTag" not in synth
+
+    def test_missing_contract_file_defaults_to_dev(self, tmp_path):
+        """A non-existent contract path defaults to the dev env (no crash)."""
+        env = synthesize_local_env(str(tmp_path / "nonexistent.yml"))
+        assert env["name"] == "dev"
+        assert env["region"] == "local"
+
+    def test_description_mentions_contract_id(self, sample_contract):
+        env = synthesize_local_env(str(sample_contract))
+        assert "msvc" in env["description"], (
+            "description should reference the contract id for traceability"
+        )