https://github.com/ansermino/go-mock-demo

https://github.com/ansermino/go-mock-demo

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• Host: GitHub
• URL: https://github.com/ansermino/go-mock-demo
• Owner: ansermino
• Created: 2021-06-09T15:40:33.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2021-06-09T15:44:08.000Z (over 3 years ago)
• Last Synced: 2024-06-20T14:17:56.548Z (6 months ago)
• Language: Go
• Size: 24.4 KB
• Stars: 2
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Go Mocking & Interfaces Demo

There are two major libs for mocking:

- [golang/mock](https://github.com/golang/mock) (we'll focus on this one)

- [testify/mock](https://github.com/stretchr/testify)

## Setup `mockgen`

```bash

# Go version < 1.16

GO111MODULE=on go get github.com/golang/mock/[email protected]

```

or

```bash

# Go 1.16+

go install github.com/golang/mock/[email protected]

```

## Generating Mocks

```bash

mockgen -source basic/basic.go -destination basic/mock/basic.go 

mockgen -source ethclient/ethclient.go -destination ethclient/mock/ethclient.go 

```

## Basic Example

This is a simple example of an interface being used for a database. We can generate mocks for this interface and then write tests using it. See `TestStoreMulti`.

Note that we explicitly specify the expected interactions with the interface, thus we can verify exactly which calls are being made. In `TestStoreMultiFailing` we have specified an expected call which is different from the one that is made given the inputs, thus the test fails.

## Ethclient Example

Here we have a struct which uses `ethclient.Client`. 

We have replaced the usage of `ethclient.Client` with an interface - very easy, much wow! 

We can generate mocks for this interface and easily test the functionality of the `ChainReader`.

Once you start using more interfaces, you can refactor your code to be much more modular, like we have with `CheckBlocks` which removes the need for the ChainReader struct.

## Notes

### Interfaces

- By convention, one-method interfaces are named by the method name plus an -er suffix or similar modification to construct an agent noun: Reader, Writer, Formatter, CloseNotifier etc. ([source](https://golang.org/doc/effective_go#interface-names))

- Smaller interfaces are better

- Be cautious which types you use as this may restrict the usefulness of an interface