How to make the function suit the _test file?

Question

Here was my code

type Queue interface {
    Push(key interface{})
    Pop() interface{}
    Contains(key interface{}) bool
    Len() int
    Keys() []interface{}
}

type QueueData struct {
    size int
    data []interface{}
}

func New(size int) *QueueData {
    return &QueueData{
        size: size,
    }
}

func (q *QueueData) IsEmpty() bool {
    return len(q.data) == 0
}

// Peek : returns the next element in the queue
func (q *QueueData) Peek() (interface{}, error) {
    if len(q.data) == 0 {
        return 0, fmt.Errorf("Queue is empty")
    }
    return q.data[0], nil
}

// Queue : adds an element onto the queue and returns an pointer to the current queue
func (q *QueueData) Push(n interface{}) *QueueData {
    if q.Len() < q.size {
        q.data = append(q.data, n)
    } else {
        q.Pop()
        q.Push(n)
    }
    return q
}

// Dequeue : removes the next element from the queue and returns its value
//func (q *QueueFix) Pop() (interface{}, error) {
func (q *QueueData) Pop() interface{} {
    if len(q.data) == 0 {
        //return 0, fmt.Errorf("Queue is empty")
        return 0
    }
    element := q.data[0]
    q.data = q.data[1:]
    //return element, nil
    return element
}

func (q *QueueData) Len() int {
    return len(q.data)
}

func (q *QueueData) Keys() []interface{} {
    return q.data
}

func (q *QueueData) Contains(key interface{}) bool {
    cont := false
    for i := 0; i < q.Len(); i++ {
        if q.data[i] == key {
            cont = true
        }
    }
    return cont
}

My Test is look like this...

var testValues = []interface{}{
    "lorem",
    "ipsum",
    1,
    2,
    3,
    "jack",
    "jill",
    "felix",
    "donking",
}

// TestPush validate evict old item policy
func TestEvictPolicy(t *testing.T) {
    size := 5
    q := New(size)

    for i, v := range testValues {
        q.Push(v)

        t.Log("current: ", q.Keys())

        // validate
        // item existence
        if !q.Contains(v) {
            t.Errorf("policy: newly inserted %v must be exists", v)
        }

        if i < 5 && q.Len() != (i+1) {
            t.Errorf("expected length %d but actual: %d", i+1, q.Len())
        } else if i >= 5 && q.Len() != 5 {
            t.Errorf("expexted length: %d but actual: %d", size, q.Len())
        }
    }
}

// TestPop validate pop item policy
func TestPop(t *testing.T) {
    size := 5
    q := New(size)

    for _, v := range testValues {
        q.Push(v)
    }

    for q.Len() > 0 {
        t.Log("current: ", q.Keys())

        v := q.Pop()

        // validate
        expect := testValues[len(testValues)-(q.Len()+1)]
        if v != expect {
            t.Error("expected %v but recevied %v", expect, v)
        }
    }

}

The test returned

.\Queue_test.go:60:4: Error call has possible formatting directive %v FAIL /C/Users/richa/go/src [build failed]

I didn't i understand how to make an code from _test.go file. Need an explain how to make the _test.go aswell. Just give some reference for this testing. like when i add EvictPolicy Function, itsay undeclared...

Answer 1

The error you are seeing

Queue_test.go:60:4: Error call has possible formatting directive %v FAIL

Looks to be referring to this line

t.Error("expected %v but recevied %v", expect, v)

On this line you called t.Error to print the error message and format the expect and v vars into the error string. But, t.Error does not format the additional arguments. It just prints them.

You should call t.Errorf like you did for your other error messages.