pangolin_exporter

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// Copyright 2023 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package collector
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import (
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	"context"
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	"testing"
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	"github.com/DATA-DOG/go-sqlmock"
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	"github.com/prometheus/client_golang/prometheus"
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	dto "github.com/prometheus/client_model/go"
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	"github.com/smartystreets/goconvey/convey"
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)
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func TestPgWALCollector(t *testing.T) {
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	db, mock, err := sqlmock.New()
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	if err != nil {
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		t.Fatalf("Error opening a stub db connection: %s", err)
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	}
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	defer db.Close()
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	inst := &instance{db: db}
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	columns := []string{"segments", "size"}
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	rows := sqlmock.NewRows(columns).
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		AddRow(47, 788529152)
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	mock.ExpectQuery(sanitizeQuery(pgWALQuery)).WillReturnRows(rows)
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	ch := make(chan prometheus.Metric)
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	go func() {
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		defer close(ch)
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		c := PGWALCollector{}
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		if err := c.Update(context.Background(), inst, ch); err != nil {
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			t.Errorf("Error calling PGWALCollector.Update: %s", err)
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		}
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	}()
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	expected := []MetricResult{
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		{labels: labelMap{}, value: 47, metricType: dto.MetricType_GAUGE},
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		{labels: labelMap{}, value: 788529152, metricType: dto.MetricType_GAUGE},
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	}
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	convey.Convey("Metrics comparison", t, func() {
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		for _, expect := range expected {
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			m := readMetric(<-ch)
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			convey.So(expect, convey.ShouldResemble, m)
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		}
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	})
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	if err := mock.ExpectationsWereMet(); err != nil {
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		t.Errorf("there were unfulfilled exceptions: %s", err)
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	}
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}
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