fix: correctly support multiValueHeaders in rust functions during dev…

…elopment (#4632)

`multiValueHeaders` was simply not forwarded from the response of the rust function

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

src/lib/functions/runtimes/rust/index.js

@@ -54,11 +54,12 @@ const invokeFunction = async ({ context, event, func, timeout }) => {
   })
 
   try {
-    const { body, headers, statusCode } = JSON.parse(stdout)
+    const { body, headers, multiValueHeaders, statusCode } = JSON.parse(stdout)
 
     return {
       body,
       headers,
+      multiValueHeaders,
       statusCode,
     }
   } catch {

tests/unit/lib/functions/runtimes/rust/index.test.js

@@ -0,0 +1,29 @@
+const test = require('ava')
+const sinon = require('sinon')
+
+const { rewiremock } = require('../../../../../integration/utils/rewiremock')
+
+const runFunctionsProxySpy = sinon.stub()
+// eslint-disable-next-line n/global-require
+const { invokeFunction } = rewiremock.proxy(() => require('../../../../../../src/lib/functions/runtimes/rust/index'), {
+  '../../../../../../src/lib/functions/local-proxy': {
+    runFunctionsProxy: runFunctionsProxySpy,
+  },
+})
+
+const invokeFunctionMacro = test.macro({
+  async exec(t, prop, expected) {
+    runFunctionsProxySpy.resolves({ stdout: JSON.stringify({ [prop]: expected }) })
+
+    const match = await invokeFunction({ func: { mainFile: '', buildData: {} } })
+    t.deepEqual(match[prop], expected)
+  },
+  title(providedTitle, prop) {
+    return `should return ${prop}`
+  },
+})
+
+test(invokeFunctionMacro, 'body', 'thebody')
+test(invokeFunctionMacro, 'headers', { 'X-Single': 'A' })
+test(invokeFunctionMacro, 'multiValueHeaders', { 'X-Multi': ['B', 'C'] })
+test(invokeFunctionMacro, 'statusCode', 200)