Add ability to write integration-tests for servers (#4332)

## Motivation and Context

This `integration-tests` directory makes it possible to write
Rust code that you can run directly against the generated servers
from the protocol test models. This makes it easier to test things
like event streams behavior and other specifics that are hard to
test with protocol tests alone.

## Description

I added a test for #4325 (showing the broken behavior) that we can use
when we fix this issue. This will also make it easy to test a number of
other open issues that have been found.

To make this easy I also added a `EventStreamSender::once` method for
convenience. The `ManualEventStream` sender could be upstreamed at a
later date so it is more broadly usable but I didn't want to pin down a
public API for it right now.
<!--- Describe your changes in detail -->

----

_By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice._

Author: rcoh

codegen-core/common-test-models/rpcv2Cbor-extras.smithy

@@ -15,10 +15,37 @@ service RpcV2CborService {
         ComplexStructOperation
         EmptyStructOperation
         SingleMemberStructOperation
-        RecursiveUnionOperation
+        RecursiveUnionOperation,
+        StreamingOperation
     ]
 }
 
+operation StreamingOperation {
+    input: StreamingOperationInput,
+    output: StreamingOperationOutput,
+    errors: [ValidationException]
+}
+
+structure StreamingOperationOutput {
+    events: Events
+}
+
+structure StreamingOperationInput {
+    events: Events
+}
+
+
+@streaming
+union Events {
+    A: Event,
+    B: Event,
+    C: Event,
+}
+
+structure Event {
+}
+
+
 // TODO(https://github.com/smithy-lang/smithy/issues/2326): Smithy should not
 // allow HTTP binding traits in this protocol.
 @http(uri: "/simple-struct-operation", method: "POST")
@@ -84,7 +111,6 @@ apply EmptyStructOperation @httpMalformedRequestTests([
                 }
             }
         }
-
     }
 ])
 
@@ -303,35 +329,26 @@ structure ErrorSerializationOperationOutput {
 structure SimpleStruct {
     blob: Blob
     boolean: Boolean
-
     string: String
-
     byte: Byte
     short: Short
     integer: Integer
     long: Long
-
     float: Float
     double: Double
-
     timestamp: Timestamp
     enum: Suit
-
     // With `@required`.
 
     @required requiredBlob: Blob
     @required requiredBoolean: Boolean
-
     @required requiredString: String
-
     @required requiredByte: Byte
     @required requiredShort: Short
     @required requiredInteger: Integer
     @required requiredLong: Long
-
     @required requiredFloat: Float
     @required requiredDouble: Double
-
     @required requiredTimestamp: Timestamp
     // @required requiredDocument: MyDocument
     @required requiredEnum: Suit
@@ -344,16 +361,14 @@ structure ComplexStruct {
     map: SimpleMap
     union: SimpleUnion
     unitUnion: UnitUnion
-
     structureList: StructList
-
     // `@required` for good measure here.
     @required complexList: ComplexList
     @required complexMap: ComplexMap
     @required complexUnion: ComplexUnion
 }
 
-structure EmptyStruct { }
+structure EmptyStruct {}
 
 structure SingleMemberStruct {
     message: String
@@ -399,7 +414,6 @@ map ComplexMap {
 union ComplexUnion {
     // Recursive path here.
     complexStruct: ComplexStruct
-
     structure: SimpleStruct
     list: SimpleList
     map: SimpleMap

codegen-server-test/build.gradle.kts

@@ -35,8 +35,16 @@ smithy {
 
 val allCodegenTests = "../codegen-core/common-test-models".let { commonModels ->
     listOf(
-        CodegenTest("crate#Config", "naming_test_ops", imports = listOf("$commonModels/naming-obstacle-course-ops.smithy")),
-        CodegenTest("casing#ACRONYMInside_Service", "naming_test_casing", imports = listOf("$commonModels/naming-obstacle-course-casing.smithy")),
+        CodegenTest(
+            "crate#Config",
+            "naming_test_ops",
+            imports = listOf("$commonModels/naming-obstacle-course-ops.smithy"),
+        ),
+        CodegenTest(
+            "casing#ACRONYMInside_Service",
+            "naming_test_casing",
+            imports = listOf("$commonModels/naming-obstacle-course-casing.smithy"),
+        ),
         CodegenTest(
             "naming_obs_structs#NamingObstacleCourseStructs",
             "naming_test_structs",
@@ -47,7 +55,7 @@ val allCodegenTests = "../codegen-core/common-test-models".let { commonModels ->
         CodegenTest(
             "smithy.protocoltests.rpcv2Cbor#RpcV2CborService",
             "rpcv2Cbor_extras",
-            imports = listOf("$commonModels/rpcv2Cbor-extras.smithy")
+            imports = listOf("$commonModels/rpcv2Cbor-extras.smithy"),
         ),
         CodegenTest(
             "com.amazonaws.constraints#ConstraintsService",
@@ -110,6 +118,12 @@ tasks["assemble"].finalizedBy("generateCargoWorkspace", "generateCargoConfigToml
 project.registerModifyMtimeTask()
 project.registerCargoCommandsTasks(layout.buildDirectory.dir(workingDirUnderBuildDir).get().asFile)
 
-tasks["test"].finalizedBy(cargoCommands(properties).map { it.toString })
+tasks.register<Exec>("cargoTestIntegration") {
+    dependsOn("assemble")
+    workingDir(projectDir.resolve("integration-tests"))
+    commandLine("cargo", "test")
+}
+
+tasks["test"].finalizedBy(cargoCommands(properties).map { it.toString }, "cargoTestIntegration")
 
 tasks["clean"].doFirst { delete("smithy-build.json") }

codegen-server-test/integration-tests/.gitignore

@@ -0,0 +1 @@
+Cargo.lock