graphql-engine/server/CONTRIBUTING.md
nizar-m a40bf10b9f run graphql tests on both http and websocket; add parallelism (close #1868) (#1921)
Examples 
1)  `
pytest --hge-urls "http://127.0.0.1:8080" --pg-urls "postgresql://admin@127.0.0.1:5432/hge_tests" -vv
`
2)  `pytest --hge-urls "http://127.0.0.1:8080"   "http://127.0.0.1:8081" --pg-urls "postgresql://admin@127.0.0.1:5432/hge_tests"  "postgresql://admin@127.0.0.1:5432/hge_tests2" -vv
`
### Solution and Design
<!-- How is this issue solved/fixed? What is the design? -->
<!-- It's better if we elaborate -->
#### Reducing execution time of tests
- The Schema setup and teardown, which were earlier done per test method, usually takes around 1 sec. 
- For mutations, the model has now been changed to only do schema setup and teardown once per test class.
-  A data setup and teardown will be done once per test instead (usually takes ~10ms).
- For the test class to get this behaviour, one can can extend the class `DefaultTestMutations`. 
    - The function  `dir()` should be define which returns the location of the configuration folder.
    - Inside the configuration folder, there should be 
        - Files `<conf_dir>/schema_setup.yaml` and `<conf_dir>/schema_teardown.yaml`, which has the metadata query executed during schema setup and teardown respectively
        - Files named `<conf_dir>/values_setup.yaml` and `<conf_dir>/values_teardown.yaml`. These files are executed to setup and remove data from the tables respectively. 

#### Running Graphql queries on both http and websockets
- Each GraphQL query/mutation is run on the both HTTP and websocket protocols
- Pytests test parameterisation is used to achieve this
- The errors over websockets are slightly different from that on HTTP
   - The code takes care of converting the errors in HTTP to errors in websockets

#### Parallel executation of tests.
- The plugin pytest-xdist helps in running tests on parallel workers.
- We are using this plugin to group tests by file and run on different workers.
- Parallel test worker processes operate on separate postgres databases(and separate graphql-engines connected to these databases). Thus tests on one worker will not affect the tests on the other worker.
- With two workers, this decreases execution times by half, as the tests on event triggers usually takes a long time, but does not consume much CPU.
2019-04-08 12:52:38 +05:30

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Markdown

# Contributing
This guide explains how to set up the graphql-engine server for development on your
own machine and how to contribute.
## Pre-requisites
- [stack](https://docs.haskellstack.org/en/stable/README/#how-to-install)
- A Postgres server (Recommended: Use docker to run a local postgres instance)
- GNU Make (optional)
- [Node.js](https://nodejs.org/en/) (v8.9+)
- libpq-dev
- psql
- python >= 3.7 with pip3
## Upgrading npm
If your npm is too old (< 5.7),
npm install -g npm@latest
or
sudo npm install -g npm@latest
or update your nodejs
## Getting pip3
sudo apt install python3-pip
## Development workflow
### Fork and clone
- Fork the repo on GitHub
- Clone your forked repo: `git clone https://github.com/<your-username>/graphql-engine`
- `cd graphql-engine`
### Compile
- compile console assets
```
cd console
npm ci
cd ..
```
- compile the server
```
cd server
stack build --fast --flag graphql-engine:local-console
```
### Run
- Make sure postgres is running (Postgres >= 9.5)
- Create a database on postgres
- Run the binary: `stack exec graphql-engine -- --database-url=<database-url> serve`
database url looks like: `postgres://<username>:<password>@<host>:<port>/<dbname>`
### Running Postgres
The easiest way is to run docker in a container
````
docker run -p 5432:5432 -d postgres:11.1
````
Test if it's running by
telnet localhost 5432
### psql
You will need psql or another client
````
sudo apt install postgresql-client
````
### Work
- Work on the feature/fix
- Add test cases if relevant
### Test
- Install the py-test dependencies:
```
pip3 install -r tests-py/requirements.txt
```
- Make sure postgres is running
- Run the graphql-engine:
```
stack exec graphql-engine -- --database-url=<database-url> serve --enable-console
```
- Set the environmental variables for event-trigger tests
```
export EVENT_WEBHOOK_HEADER="MyEnvValue"
export WEBHOOK_FROM_ENV="http://127.0.0.1:5592"
```
- Run tests:
```
cd tests-py
pytest --hge-urls http://127.0.0.1:8080 --pg-urls <database_url> -vv
```
### Create Pull Request
- Make sure your commit messages meet the [guidelines](../CONTRIBUTING.md).
- Create a pull request from your forked repo to the main repo.
- Every pull request will automatically build and run the tests.
## Code conventions
This helps enforce a uniform style for all committers.
- Compiler warnings are turned on, make sure your code has no warnings.
- Use [hlint](https://github.com/ndmitchell/hlint) to make sure your code has no warnings.
- Use [stylish-haskell](https://github.com/jaspervdj/stylish-haskell) to format your code.