From c0478aae0a967f5ce6f7c8696ad33cd510ad6af8 Mon Sep 17 00:00:00 2001
From: Martin Petrov <357181+mpetrov@users.noreply.github.com>
Date: Mon, 11 Mar 2019 10:36:11 -0400
Subject: [PATCH] Generate ClientCallUnary test stubs. (#398)

* Generate ClientCallUnary test stubs.

This simplifies testing for async calls, e.g. a failing request could
be simulated with something like:
```
  override func get(_ request: Echo_EchoRequest, metadata customMetadata: Metadata, completion: @escaping (Echo_EchoResponse?, CallResult) -> Void) throws -> Echo_EchoGetCall {
    completion(nil, .error(statusCode: .notFound))
    return Echo_EchoGetCallTestStub()
  }
```

* Remove generics from unary call stub.
---
 Sources/Examples/Echo/Generated/echo.grpc.swift     | 4 ++++
 Sources/SwiftGRPC/Runtime/ClientCallUnary.swift     | 7 +++++++
 Sources/protoc-gen-swiftgrpc/Generator-Client.swift | 8 ++++++++
 3 files changed, 19 insertions(+)

diff --git a/Sources/Examples/Echo/Generated/echo.grpc.swift b/Sources/Examples/Echo/Generated/echo.grpc.swift
index 87ee13fc3..03eb7c362 100644
--- a/Sources/Examples/Echo/Generated/echo.grpc.swift
+++ b/Sources/Examples/Echo/Generated/echo.grpc.swift
@@ -31,6 +31,10 @@ fileprivate final class Echo_EchoGetCallBase: ClientCallUnaryBase<Echo_EchoReque
   override class var method: String { return "/echo.Echo/Get" }
 }
 
+class Echo_EchoGetCallTestStub: ClientCallUnaryTestStub, Echo_EchoGetCall {
+  override class var method: String { return "/echo.Echo/Get" }
+}
+
 internal protocol Echo_EchoExpandCall: ClientCallServerStreaming {
   /// Do not call this directly, call `receive()` in the protocol extension below instead.
   func _receive(timeout: DispatchTime) throws -> Echo_EchoResponse?
diff --git a/Sources/SwiftGRPC/Runtime/ClientCallUnary.swift b/Sources/SwiftGRPC/Runtime/ClientCallUnary.swift
index b70441f5c..1cb3823e2 100644
--- a/Sources/SwiftGRPC/Runtime/ClientCallUnary.swift
+++ b/Sources/SwiftGRPC/Runtime/ClientCallUnary.swift
@@ -56,3 +56,10 @@ open class ClientCallUnaryBase<InputType: Message, OutputType: Message>: ClientC
     return self
   }
 }
+
+/// Simple fake implementation of `ClientCallUnary`.
+open class ClientCallUnaryTestStub: ClientCallUnary {
+  open class var method: String { fatalError("needs to be overridden") }
+
+  open func cancel() {}
+}
diff --git a/Sources/protoc-gen-swiftgrpc/Generator-Client.swift b/Sources/protoc-gen-swiftgrpc/Generator-Client.swift
index d3cf3e269..10f21ae94 100644
--- a/Sources/protoc-gen-swiftgrpc/Generator-Client.swift
+++ b/Sources/protoc-gen-swiftgrpc/Generator-Client.swift
@@ -66,6 +66,14 @@ extension Generator {
     println("override class var method: String { return \(methodPath) }")
     outdent()
     println("}")
+    if options.generateTestStubs {
+      println()
+      println("class \(callName)TestStub: ClientCallUnaryTestStub, \(callName) {")
+      indent()
+      println("override class var method: String { return \(methodPath) }")
+      outdent()
+      println("}")
+    }
     println()
   }