expect(...).to.be.called

[marekkirejczyk]

Add matchers for checking if the mock contract function was called with specific arguments.

Example:

it('calls balanceOf', async () => {
  await tokenMock.balanceOf.returns('1000000')); 
  await someContract.check();
  await expect(tokenMock.balanceOf).to.be.called
});

[sz-piotr]

It is important to not interfere with https://www.npmjs.com/package/sinon-chai

[sz-piotr]

This is what we came up with @Jozwiaczek

expect(contract).to.be.ethCalled
expect([contract, 'function']).to.be.ethCalled
expect([contract, 'function']).to.be.ethCalledWith(arg1, arg2)

[marekkirejczyk]

Originally proposed syntax is not possible to implement.
Below we present three major syntax proposals we came up with on the call with @sz-piotr .
We will vote on the syntax internally on Ethworks slack to see what are our devs preference (hoping it will extrapolate to a wider audience)

1) 
expect('functionName').to.be.calledOn(contract)
expect('functionName').to.be.calledOn(contract).withArgs(args)

2) 
expect(contract).to.be.ethCalled
expect([contract, 'function']).to.be.ethCalled
expect([contract, 'function']).to.be.ethCalledWith(arg1, arg2)

3) 
expect(contract).to.be.calledWith('functionName')
expect(contract).to.be.calledWith('functionName', ...args)
expect(contract).to.be.calledWith('functionName').withArgs(args)

[marekkirejczyk]

The results are:
Option 1) - 6 votes
Option 2) - 1 vote
Option 3) - 3 votes

[marekkirejczyk]

Voted Option 1) still is impossible to implement (name collision with sinon-chai, .not. impossible to implement), modified proposals below.

1)
expect('functionName').to.be
  .calledOnContract(contract)
expect('functionName').not.to.be.calledOnContract(contract)
expect('functionName').to.be.calledOnContract(contract).withArgs(args)
expect('functionName')
  .not.to.be.calledOnContract(contract)
  .withArgs(args)

2) 
expect('functionName').to.be.calledOnContract(contract)
expect('functionName').not.to.be.calledOnContract(contract)
expect('functionName').to.be.calledOnContractWith(contract, ...)
expect('functionName').not.to.be.calledOnContractWith(contract, ...)

3) Other ideas:
expect('functionName').to.be.triggeredOn(contract)
expect('functionName').to.be.sendMsgTo(contract)

On the call with @sz-piotr @Jozwiaczek we decided to implement 2).