// Copyright 2018 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain 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 testutil

import (
	"strings"
	"testing"

	"github.com/prometheus/client_golang/prometheus"
)

func TestCollectAndCompare(t *testing.T) {
	const metadata = `
		# HELP some_total A value that represents a counter.
		# TYPE some_total counter
	`

	c := prometheus.NewCounter(prometheus.CounterOpts{
		Name: "some_total",
		Help: "A value that represents a counter.",
		ConstLabels: prometheus.Labels{
			"label1": "value1",
		},
	})
	c.Inc()

	expected := `

		some_total{ label1 = "value1" } 1
	`

	if err := CollectAndCompare(c, strings.NewReader(metadata+expected), "some_total"); err != nil {
		t.Errorf("unexpected collecting result:\n%s", err)
	}
}

func TestNoMetricFilter(t *testing.T) {
	const metadata = `
		# HELP some_total A value that represents a counter.
		# TYPE some_total counter
	`

	c := prometheus.NewCounter(prometheus.CounterOpts{
		Name: "some_total",
		Help: "A value that represents a counter.",
		ConstLabels: prometheus.Labels{
			"label1": "value1",
		},
	})
	c.Inc()

	expected := `
		some_total{label1="value1"} 1
	`

	if err := CollectAndCompare(c, strings.NewReader(metadata+expected)); err != nil {
		t.Errorf("unexpected collecting result:\n%s", err)
	}
}

func TestMetricNotFound(t *testing.T) {
	const metadata = `
		# HELP some_other_metric A value that represents a counter.
		# TYPE some_other_metric counter
	`

	c := prometheus.NewCounter(prometheus.CounterOpts{
		Name: "some_total",
		Help: "A value that represents a counter.",
		ConstLabels: prometheus.Labels{
			"label1": "value1",
		},
	})
	c.Inc()

	expected := `
		some_other_metric{label1="value1"} 1
	`

	expectedError := `
metric output does not match expectation; want:

# HELP some_other_metric A value that represents a counter.
# TYPE some_other_metric counter
some_other_metric{label1="value1"} 1


got:

# HELP some_total A value that represents a counter.
# TYPE some_total counter
some_total{label1="value1"} 1

`

	err := CollectAndCompare(c, strings.NewReader(metadata+expected))
	if err == nil {
		t.Error("Expected error, got no error.")
	}

	if err.Error() != expectedError {
		t.Errorf("Expected\n%#+v\nGot:\n%#+v\n", expectedError, err.Error())
	}
}