# Example Tests

In the previous sections we showed you how you can call() or post() function requests. We also created a few wrapper functions to simplify calling these functions even further. Now we will look at how to use the SoloContext to create full-blown tests for the dividend example smart contract.

Let's start with a simple test. We are going to use the member function to add a valid new member/factor combination to the member group.

func TestAddMemberOk(t *testing.T) {    ctx := wasmsolo.NewSoloContext(t, dividend.ScName, dividend.OnLoad)    member1 := ctx.NewSoloAgent()    dividendMember(ctx, member1, 100)    require.NoError(t, ctx.Err)}

The above test first deploys the dividend smart contract to a new chain, and returns a SoloContext ctx. Then it uses ctx to create a new SoloAgent. A SoloAgent is an actor with its own Tangle address, which contains utxodb.FundsFromFaucetAmount tokens. The SoloAgent can be used whenever an address or agent ID needs to be provided, it can be used to sign a token transfer from its address, and can be used to inspect the balance of tokens on the address.

In this case, we simply create member, and pass it to the member function, which will receive the address of member1 and a dispersal factor of 100. Finally, we check if ctx has received an error during the execution of the call. Remember that the only way to pass an error from a WasmLib function call is through a panic() call. The code that handles the actual call will intercept any panic() that was raised, and return an error. The SoloContext saves this error for later inspection, because the function descriptor used in the call itself has no way of passing back this error.

The next two example tests each call the same member function in the exact same way, but in both cases one required parameter is omitted. The idea is to test that the function properly panics by checking the ctx.Err value is not nil after the call. Finally, the error message text is checked to see if it contains the correct error message.

func TestAddMemberFailMissingAddress(t *testing.T) {    ctx := wasmsolo.NewSoloContext(t, dividend.ScName, dividend.OnLoad)    member := dividend.ScFuncs.Member(ctx)    member.Params.Factor().SetValue(100)    member.Func.TransferIotas(1).Post()    require.Error(t, ctx.Err)    require.True(t, strings.HasSuffix(ctx.Err.Error(), "missing mandatory address"))}func TestAddMemberFailMissingFactor(t \*testing.T) {    ctx := wasmsolo.NewSoloContext(t, dividend.ScName, dividend.OnLoad)    member1 := ctx.NewSoloAgent()    f := dividend.ScFuncs.Member(ctx)    f.Params.Address().SetValue(member1.ScAddress())    f.Func.TransferIotas(1).Post()    require.Error(t, ctx.Err)    require.True(t, strings.HasSuffix(ctx.Err.Error(), "missing mandatory factor"))}

Each test has to set up the chain/contract/context from scratch. We will often use a specific setupTest() function to do all setup work that is shared by many tests.

We cannot use the dividendMember wrapper function in these two tests because of the missing required function parameters. So we have copy/pasted the code, and removed the Params initialization we wanted to be missing.

Now let's see a more complex example:

func TestDivide1Member(t *testing.T) {    ctx := wasmsolo.NewSoloContext(t, dividend.ScName, dividend.OnLoad)    member1 := ctx.NewSoloAgent()    dividendMember(ctx, member1, 100)    require.NoError(t, ctx.Err)    require.EqualValues(t, 1, ctx.Balance(nil))    dividendDivide(ctx, 99)    require.NoError(t, ctx.Err)    // 99 from divide() + 1 from the member() call    require.EqualValues(t, utxodb.FundsFromFaucetAmount+100, member1.Balance())    require.EqualValues(t, 0, ctx.Balance(nil))}

The first half of the code is identical to our first test above. We set up the test, create an agent, set the factor for that agent to 100, and verify that no error occurred. Then in the next line we verify that the smart contract associated with ctx now holds a balance of 1 iota. This is the token that was transferred as part of the Post() request inside the dividendMember() function.

Next we transfer 99 iotas as part of thePost() request to the divide function. We subsequently check that no error has occurred. Finally, we expect the balance of member1 address to have increased by the total of 100 tokens that were stored in the dividend smart contract account, as 100/100th of the tokens should have been sent to member1. And the contract account should end up empty.

func TestDivide3Members(t *testing.T) {    ctx := wasmsolo.NewSoloContext(t, dividend.ScName, dividend.OnLoad)    member1 := ctx.NewSoloAgent()    dividendMember(ctx, member1, 25)    require.NoError(t, ctx.Err)    member2 := ctx.NewSoloAgent()    dividendMember(ctx, member2, 50)    require.NoError(t, ctx.Err)    member3 := ctx.NewSoloAgent()    dividendMember(ctx, member3, 75)    require.NoError(t, ctx.Err)    require.EqualValues(t, 3, ctx.Balance(nil))    dividendDivide(ctx, 97)    require.NoError(t, ctx.Err)    // 97 from divide() + 3 from the member() calls    require.EqualValues(t, utxodb.FundsFromFaucetAmount+16, member1.Balance())    require.EqualValues(t, utxodb.FundsFromFaucetAmount+33, member2.Balance())    require.EqualValues(t, utxodb.FundsFromFaucetAmount+50, member3.Balance())    // 1 remaining due to fractions    require.EqualValues(t, 1, ctx.Balance(nil))}

This function creates 3 agents, and associates factors of 25, 50, and 75 respectively to them. Since that required 3 member requests, the contract account should now contain 3 iotas. Next the divide function is called, with 97 iotas passed to it, for a total of 100 into the contract account.

After this we verify that each agent has been distributed tokens according to its relative factor. Those factors are 25/150th, 50/150th, and 75/150th, respectively. Note that we cannot transfer fractional tokens, so we truncate to the nearest integer and ultimately are left with 1 iota in the contract account. This 1 iota will be part of the dispersal amount when the next divide call request is executed.

We can test this behavior by adding extra calls to divide at the end of this test like this:

    dividendDivide(ctx, 100)    require.NoError(t, ctx.Err)    // 100 from divide() + 1 remaining    require.EqualValues(t, utxodb.FundsFromFaucetAmount+16+16, member1.Balance())    require.EqualValues(t, utxodb.FundsFromFaucetAmount+33+33, member2.Balance())    require.EqualValues(t, utxodb.FundsFromFaucetAmount+50+50, member3.Balance())    // now we have 2 remaining due to fractions    require.EqualValues(t, 2, ctx.Balance(nil))    dividendDivide(ctx, 100)    require.NoError(t, ctx.Err)    // 100 from divide() + 2 remaining    require.EqualValues(t, utxodb.FundsFromFaucetAmount+16+16+17, member1.Balance())    require.EqualValues(t, utxodb.FundsFromFaucetAmount+33+33+34, member2.Balance())    require.EqualValues(t, utxodb.FundsFromFaucetAmount+50+50+51, member3.Balance())    // managed to give every one an exact integer amount, so no remainder    require.EqualValues(t, 0, ctx.Balance(nil))

After the final divide call, we ended up with the exact amounts to disperse, so no remainder iotas were left in the contract account.

Each divide is cumulative to the balances of the members. We have highlighted this by indicating the separate increases after every divide call.

Finally, we will show how to test Views and/or Funcs that return a result. Since solo executes post() requests synchronously, it is possible to have a Func return a result and test for certain result values.

func TestGetFactor(t *testing.T) {    ctx := wasmsolo.NewSoloContext(t, dividend.ScName, dividend.OnLoad)    member1 := ctx.NewSoloAgent()    dividendMember(ctx, member1, 25)    require.NoError(t, ctx.Err)    member2 := ctx.NewSoloAgent()    dividendMember(ctx, member2, 50)    require.NoError(t, ctx.Err)    member3 := ctx.NewSoloAgent()    dividendMember(ctx, member3, 75)    require.NoError(t, ctx.Err)    require.EqualValues(t, 3, ctx.Balance(nil))    value := dividendGetFactor(ctx, member3)    require.NoError(t, ctx.Err)    require.EqualValues(t, 75, value)    value = dividendGetFactor(ctx, member2)    require.NoError(t, ctx.Err)    require.EqualValues(t, 50, value)    value = dividendGetFactor(ctx, member1)    require.NoError(t, ctx.Err)    require.EqualValues(t, 25, value)}

Here we first set up the same 3 dispersion factors, and then we retrieve the dispersion factors for each member in reverse order and verify its value.

In the next section we will describe a few more helper member functions of the SoloContext.