test(tests): re-enable the Python edge integration test

[jsteinich]

Related issue

Follow-up from the review on #400, point 2. #400 is closed; this is the durable half of its regression coverage.

Description

test/python/edge/test.ts has been describe.skip'd since 3acb935 (1 December 2022), waiting on aws/jsii#3866, with the stated intent to "re-add them when updating JSII". That fix shipped shortly after, and the JSII update has since landed (#395: jsii 6.0, jsii-pacmak 1.140.0) — but the skip was never lifted.

Python is the only language whose edge test does not run. TypeScript, Go, Java and C# all do.

That gap has a concrete cost: it is why #311's cross-language compile coverage never saw the broken Python provider import, which only surfaced once CI could reach Terraform >= 1.8 (#398) — and then via the python-documentation example rather than a test aimed at it.

main.py calls edge.provider.EdgeProvider(...), so beforeAll's synth imports the generated edge.provider module — exactly the module whose __init__.py carried the unresolvable import. A regression there fails the suite loudly, at the import.

Two stale assertions, and why they were wrong

Re-enabling produced 18 passed / 2 failed. The suite is substantially intact after three years dormant; both failures were expectations that had never once executed.

1. A typo. The numList expectation read ...reqnum)} — a stray closing paren — where synth produces ...reqnum}.

2. A wrong assumption about Fn.lookup. The map expectations assumed every Fn.lookup(map, key, default) renders as a Terraform lookup(). It does not. Fn.lookup (packages/cdktn/src/terraform-functions.ts:41) emits lookup() only when the default is truthy:

static lookup(inputMap: any, key: string, defaultValue?: any) {
  if (defaultValue) return Fn._lookup(inputMap, key, [defaultValue]);
  return asAny(propertyAccess(inputMap, [key])); // -> renders inputMap[key]
}

The fixture passes the same Fn.lookup(...) call for all six attributes, with different defaults:

attribute	default	truthy	renders as
reqMap	false	no	${map_resource.map.reqMap.key1}
optMap	"missing"	yes	${lookup(map_resource.map.optMap, "key1", "missing")}
computedMap	0	no	${map_resource.map.computedMap.key1}

So the deciding factor is the truthiness of the default, not whether the attribute is required, optional or computed. The corrected expectations match, and are now identical to test/typescript/edge/test.ts.

Only the first failing assertion in each block is reported by jest, so the rest of the map block was corrected at the same time rather than surfacing them one CI run at a time.

These pin current behaviour, not necessarily correct behaviour (#416)

Worth flagging rather than burying: that truthiness guard looks like a bug. Fn.lookup(map, "key", false) reads as "return false if the key is missing", but the falsy default is discarded and the emitted expression becomes a bare property access — which errors on a missing key instead of returning the default. The guard should almost certainly be defaultValue !== undefined.

Filed as #416. I have deliberately not changed it here. This PR is test coverage; altering Fn.lookup is a behavioural change to the construct library with its own blast radius, and it would be wrong to smuggle it in. If it is fixed, these expectations move with it — and at that point the edge tests will be the thing that proves the fix, which is rather the point of un-skipping them.

Note this also means the equivalent TypeScript assertions were changed to match this behaviour in 09ac17b ("chore: fix assertions", Aug 2023) with no rationale recorded.

Testing

CI on this branch: 257 pass, 0 fail, 1 skip (windows_integration, if: false). Both python/edge jobs pass, on Terraform 1.5.7 and 1.16.1.

🤖 Generated with Claude Code