Negative HTTP/2 Interop Test Case Descriptions
=======================================

Client and server use
[test.proto](../src/proto/grpc/testing/test.proto).

Server
------
The code for the custom http2 server can be found
[here](https://github.com/grpc/grpc/tree/master/test/http2_test).
It is responsible for handling requests and sending responses, and also for 
fulfilling the behavior of each particular test case.

Server should accept these arguments:
* --port=PORT
  * The port the server will run on. For example, "8080"
* --test_case=TESTCASE
  * The name of the test case to execute. For example, "goaway"

Client
------

Clients implement test cases that test certain functionality. Each client is
provided the test case it is expected to run as a command-line parameter. Names
should be lowercase and without spaces.

Clients should accept these arguments:
* --server_host=HOSTNAME
    * The server host to connect to. For example, "localhost" or "127.0.0.1"
* --server_port=PORT
    * The server port to connect to. For example, "8080"
* --test_case=TESTCASE
    * The name of the test case to execute. For example, "goaway"

Note
-----

Note that the server and client must be invoked with the same test case or else
the test will be meaningless. For convenience, we provide a shell script wrapper
that invokes both server and client at the same time, with the same test_case.
This is the preferred way to run these tests.

## Test Cases

### goaway

This test verifies that the client correctly responds to a goaway sent by the
server. The client should handle the goaway by switching to a new stream without
the user application having to do a thing.

Client Procedure:
 1. Client sends two UnaryCall requests (and sleeps for 1 second in-between).
 TODO: resolve [9300](https://github.com/grpc/grpc/issues/9300) and remove the 1 second sleep
 
    ```
    {
      response_size: 314159
      payload:{
        body: 271828 bytes of zeros
      }
    }
    ```

Client asserts:
* Both calls are successful.
* Response payload body is 314159 bytes in size.

Server Procedure:
  1. Server sends a GOAWAY after receiving the first UnaryCall.

Server asserts:
* Two different connections were used from the client.

### rst_after_header

This test verifies that the client fails correctly when the server sends a
RST_STREAM immediately after sending headers to the client.

Procedure:
 1. Client sends UnaryCall with:
 
    ```
    {
      response_size: 314159
      payload:{
        body: 271828 bytes of zeros
      }
    }
    ```

Client asserts:
* Call was not successful.

Server Procedure:
  1. Server sends a RST_STREAM with error code 0 after sending headers to the client.
  
*At the moment the error code and message returned are not standardized throughout all
languages. Those checks will be added once all client languages behave the same way. [#9142](https://github.com/grpc/grpc/issues/9142) is in flight.*

### rst_during_data

This test verifies that the client fails "correctly" when the server sends a
RST_STREAM halfway through sending data to the client.

Procedure:
 1. Client sends UnaryCall with:
 
    ```
    {
      response_size: 314159
      payload:{
        body: 271828 bytes of zeros
      }
    }
    ```

Client asserts:
* Call was not successful.

Server Procedure:
  1. Server sends a RST_STREAM with error code 0 after sending half of 
     the requested data to the client.

### rst_after_data

This test verifies that the client fails "correctly" when the server sends a
RST_STREAM after sending all of the data to the client.

Procedure:
 1. Client sends UnaryCall with:
 
    ```
    {
      response_size: 314159
      payload:{
        body: 271828 bytes of zeros
      }
    }
    ```

Client asserts:
* Call was not successful.

Server Procedure:
  1. Server sends a RST_STREAM with error code 0 after sending all of the
  data to the client.

*Certain client languages allow the data to be accessed even though a RST_STREAM
was encountered. Once all client languages behave this way, checks will be added on
the incoming data.*

### ping

This test verifies that the client correctly acknowledges all pings it gets from the
server.

Procedure:
 1. Client sends UnaryCall with:
 
    ```
    {
      response_size: 314159
      payload:{
        body: 271828 bytes of zeros
      }
    }
    ```
  
Client asserts:
* call was successful.
* response payload body is 314159 bytes in size.

Server Procedure:
  1. Server tracks the number of outstanding pings (i.e. +1 when it sends a ping, and -1 
  when it receives an ack from the client).
  2. Server sends pings before and after sending headers, also before and after sending data.
  
Server Asserts:
* Number of outstanding pings is 0 when the connection is lost.

### max_streams

This test verifies that the client observes the MAX_CONCURRENT_STREAMS limit set by the server.

Client Procedure:
  1. Client sends initial UnaryCall to allow the server to update its MAX_CONCURRENT_STREAMS settings.
  2. Client concurrently sends 10 UnaryCalls.
  
Client Asserts:
* All UnaryCalls were successful, and had the correct type and payload size.
 
Server Procedure:
  1. Sets MAX_CONCURRENT_STREAMS to one after the connection is made.

*The assertion that the MAX_CONCURRENT_STREAMS limit is upheld occurs in the http2 library we used.*