// Copyright © 2010-12 Qtrac Ltd.
//
// This program or package and any associated files are licensed under the
// Apache License, Version 2.0 (the "License"); you may not use these files
// except in compliance with the License. You can get a copy of the License
// at: http://www.apache.org/licenses/LICENSE-2.0.
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package stack_test

import (
	"github.com/henrylee2cn/algorithm/evaler/stack"
	"testing"
)

func TestStack(t *testing.T) {
	count := 1
	var aStack stack.Stack
	assertTrue(t, aStack.Len() == 0, "expected empty Stack", count) // 1
	count++
	assertTrue(t, aStack.Cap() == 0, "expected empty Stack", count) // 2
	count++
	assertTrue(t, aStack.IsEmpty(), "expected empty Stack", count) // 3
	count++
	value, err := aStack.Pop()
	assertTrue(t, value == nil, "expected nil value", count) // 4
	count++
	assertTrue(t, err != nil, "expected error", count) // 5
	count++
	value1, err := aStack.Top()
	assertTrue(t, value1 == nil, "expected nil value", count) // 6
	count++
	assertTrue(t, err != nil, "expected error", count) // 7
	count++
	aStack.Push(1)
	aStack.Push(2)
	aStack.Push("three")
	assertTrue(t, aStack.Len() == 3, "expected nonempty Stack", count) // 8
	count++
	assertTrue(t, aStack.IsEmpty() == false, "expected nonempty Stack",
		count) // 9
	count++
	value2, err := aStack.Pop()
	assertEqualString(t, value2.(string), "three", "unexpected text",
		count) // 10
	count++
	assertTrue(t, err == nil, "no error expected", count) // 11
	count++
	value3, err := aStack.Top()
	assertTrue(t, value3 == 2, "unexpected number", count) // 12
	count++
	assertTrue(t, err == nil, "no error expected", count) // 13
	count++
	aStack.Pop()
	assertTrue(t, aStack.Len() == 1, "expected nonempty Stack", count) //14
	count++
	assertTrue(t, aStack.IsEmpty() == false, "expected nonempty Stack",
		count) // 15
	count++
	value4, err := aStack.Pop()
	assertTrue(t, value4 == 1, "unexpected number", count) // 16
	count++
	assertTrue(t, err == nil, "no error expected", count) // 17
	count++
	assertTrue(t, aStack.Len() == 0, "expected empty Stack", count) // 18
	count++
	assertTrue(t, aStack.IsEmpty(), "expected empty Stack", count) // 19
	count++
}

// assertTrue() calls testing.T.Error() with the given message if the
// condition is false.
func assertTrue(t *testing.T, condition bool, message string, id int) {
	if !condition {
		t.Errorf("#%d: %s", id, message)
	}
}

// assertEqualString() calls testing.T.Error() with the given message if
// the given strings are not equal.
func assertEqualString(t *testing.T, a, b string, message string, id int) {
	if a != b {
		t.Errorf("#%d: %s \"%s\" !=\n\"%s\"", id, message, a, b)
	}
}
