Function TestIPVSCollectorResponse

collector/ipvs_linux_test.go:165–222

(t *testing.T)

}

func TestIPVSCollectorResponse(t *testing.T) {
	testcases := []struct {
		labels      string
		metricsFile string
	}{
		{"<none>", "fixtures/ip_vs_result.txt"},
		{"", "fixtures/ip_vs_result_lbs_none.txt"},
		{"local_port", "fixtures/ip_vs_result_lbs_local_port.txt"},
		{"local_address,local_port", "fixtures/ip_vs_result_lbs_local_address_local_port.txt"},
	}
	for _, test := range testcases {
		t.Run(test.labels, func(t *testing.T) {
			args := []string{"--path.procfs", "fixtures/proc"}
			if test.labels != "<none>" {
				args = append(args, "--collector.ipvs.backend-labels="+test.labels)
			}
			if _, err := kingpin.CommandLine.Parse(args); err != nil {
				t.Fatal(err)
			}
			collector, err := NewIPVSCollector(slog.New(slog.NewTextHandler(io.Discard, nil)))
			if err != nil {
				t.Fatal(err)
			}
			registry := prometheus.NewRegistry()
			registry.MustRegister(miniCollector{c: collector})

			rw := httptest.NewRecorder()
			promhttp.InstrumentMetricHandler(registry, promhttp.HandlerFor(registry, promhttp.HandlerOpts{})).ServeHTTP(rw, &http.Request{})

			wantMetrics, err := os.ReadFile(test.metricsFile)
			if err != nil {
				t.Fatalf("unable to read input test file %s: %s", test.metricsFile, err)
			}

			wantLines := strings.Split(string(wantMetrics), "\n")
			gotLines := strings.Split(string(rw.Body.String()), "\n")
			gotLinesIdx := 0

			// Until the Prometheus Go client library offers better testability
			// (https://github.com/prometheus/client_golang/issues/58), we simply compare
			// verbatim text-format metrics outputs, but ignore any lines we don't have
			// in the fixture. Put differently, we are only testing that each line from
			// the fixture is present, in the order given.
		wantLoop:
			for _, want := range wantLines {
				for _, got := range gotLines[gotLinesIdx:] {
					if want == got {
						// this is a line we are interested in, and it is correct
						continue wantLoop
					}
					gotLinesIdx++
				}
				// if this point is reached, the line we want was missing
				t.Fatalf("Missing expected output line(s), first missing line is %s", want)
			}
		})
	}
}