test: improve coverage on http and metrics (#5712)

* chore(tests): Adding in missing tests for CustomRoundTrip struct.

* chore(tests): Adding in missing unit test.

* chore(tests): Refactored and addressed missing coverage in models.go

pkg/http/http_test.go

@@ -18,9 +18,12 @@ package http
 
 import (
 	"fmt"
+	"io"
 	"net/http"
+	"net/url"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
@@ -57,3 +60,98 @@ func TestNewInstrumentedClient(t *testing.T) {
 	_, ok = result2.Transport.(*CustomRoundTripper)
 	require.True(t, ok)
 }
+
+func TestCancelRequest(t *testing.T) {
+	for _, tt := range []struct {
+		title              string
+		customRoundTripper CustomRoundTripper
+		request            *http.Request
+	}{
+		{
+			title:              "CancelRequest does nothing",
+			customRoundTripper: CustomRoundTripper{},
+			request:            &http.Request{},
+		},
+	} {
+		t.Run(tt.title, func(t *testing.T) {
+			tt.customRoundTripper.CancelRequest(tt.request)
+		})
+	}
+}
+
+type mockRoundTripper struct {
+	response *http.Response
+	error    error
+}
+
+func (mrt mockRoundTripper) RoundTrip(*http.Request) (*http.Response, error) {
+	return mrt.response, mrt.error
+}
+
+func TestRoundTrip(t *testing.T) {
+	for _, tt := range []struct {
+		title            string
+		nextRoundTripper mockRoundTripper
+		request          *http.Request
+		method           string
+		url              string
+		body             io.Reader
+
+		expectError      bool
+		expectedResponse *http.Response
+	}{
+		{
+			title:            "RoundTrip returns no error",
+			nextRoundTripper: mockRoundTripper{},
+			request: &http.Request{
+				Method: http.MethodGet,
+				URL: &url.URL{
+					Scheme: "HTTPS",
+					Host:   "test.local",
+					Path:   "/path",
+				},
+				Body: nil,
+			},
+			expectError:      false,
+			expectedResponse: nil,
+		},
+		{
+			title: "RoundTrip extracts status from request",
+			nextRoundTripper: mockRoundTripper{
+				response: &http.Response{
+					StatusCode: http.StatusOK,
+				},
+			},
+			request: &http.Request{
+				Method: http.MethodGet,
+				URL: &url.URL{
+					Scheme: "HTTPS",
+					Host:   "test.local",
+					Path:   "/path",
+				},
+				Body: nil,
+			},
+			expectError: false,
+			expectedResponse: &http.Response{
+				StatusCode: http.StatusOK,
+			},
+		},
+	} {
+		t.Run(tt.title, func(t *testing.T) {
+			req, err := http.NewRequest(tt.method, tt.url, tt.body)
+			customRoundTripper := CustomRoundTripper{
+				next: tt.nextRoundTripper,
+			}
+
+			resp, err := customRoundTripper.RoundTrip(req)
+
+			if tt.expectError {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+			}
+
+			assert.Equal(t, tt.expectedResponse, resp)
+		})
+	}
+}

pkg/metrics/metrics_test.go

@@ -72,6 +72,14 @@ func TestMustRegister(t *testing.T) {
 			},
 			expected: 0,
 		},
+		{
+			name: "skip if metric exists",
+			metrics: []IMetric{
+				NewGaugeWithOpts(prometheus.GaugeOpts{Name: "existing_metric"}),
+				NewGaugeWithOpts(prometheus.GaugeOpts{Name: "existing_metric"}),
+			},
+			expected: 1,
+		},
 	}
 
 	for _, tt := range tests {

pkg/metrics/models_test.go

@@ -113,21 +113,75 @@ func TestGaugeV_SetWithLabels(t *testing.T) {
 	assert.Len(t, m.Label, 2)
 }
 
-func TestNewBuildInfoCollector(t *testing.T) {
-	metric := NewGaugeFuncMetric(prometheus.GaugeOpts{
-		Namespace: Namespace,
-		Name:      "build_info",
-		ConstLabels: prometheus.Labels{
-			"version":   "0.0.1",
-			"goversion": "1.24",
-			"arch":      "arm64",
+func TestNewGaugeFuncMetric(t *testing.T) {
+	tests := []struct {
+		name                    string
+		metricName              string
+		subSystem               string
+		constLabels             prometheus.Labels
+		expectedFqName          string
+		expectedDescString      string
+		expectedGaugeFuncReturn float64
+	}{
+		{
+			name:       "NewGaugeFuncMetric returns build_info",
+			metricName: "build_info",
+			subSystem:  "",
+			constLabels: prometheus.Labels{
+				"version":   "0.0.1",
+				"goversion": "1.24",
+				"arch":      "arm64",
+			},
+			expectedFqName:          "external_dns_build_info",
+			expectedDescString:      "version=\"0.0.1\"",
+			expectedGaugeFuncReturn: 1,
 		},
-	})
+		{
+			name:                    "NewGaugeFuncMetric subsystem alters name",
+			metricName:              "metricName",
+			subSystem:               "subSystem",
+			constLabels:             prometheus.Labels{},
+			expectedFqName:          "external_dns_subSystem_metricName",
+			expectedDescString:      "",
+			expectedGaugeFuncReturn: 1,
+		},
+		{
+			name:                    "NewGaugeFuncMetric GaugeFunc returns 1",
+			metricName:              "metricName",
+			subSystem:               "",
+			constLabels:             prometheus.Labels{},
+			expectedFqName:          "external_dns_metricName",
+			expectedDescString:      "",
+			expectedGaugeFuncReturn: 1,
+		},
+	}
 
-	desc := metric.GaugeFunc.Desc()
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			metric := NewGaugeFuncMetric(prometheus.GaugeOpts{
+				Namespace:   Namespace,
+				Name:        tt.metricName,
+				Subsystem:   tt.subSystem,
+				ConstLabels: tt.constLabels,
+			})
 
-	assert.Equal(t, "external_dns_build_info", reflect.ValueOf(desc).Elem().FieldByName("fqName").String())
-	assert.Contains(t, desc.String(), "version=\"0.0.1\"")
+			desc := metric.GaugeFunc.Desc()
+
+			assert.Equal(t, tt.expectedFqName, reflect.ValueOf(desc).Elem().FieldByName("fqName").String())
+			assert.Contains(t, desc.String(), tt.expectedDescString)
+
+			testRegistry := prometheus.NewRegistry()
+			err := testRegistry.Register(metric.GaugeFunc)
+			require.NoError(t, err)
+
+			metricFamily, err := testRegistry.Gather()
+			require.NoError(t, err)
+			require.Len(t, metricFamily, 1)
+
+			require.NotNil(t, metricFamily[0].Metric[0].Gauge)
+			assert.InDelta(t, tt.expectedGaugeFuncReturn, metricFamily[0].Metric[0].GetGauge().GetValue(), 0.0001)
+		})
+	}
 }
 
 func TestSummaryV_SetWithLabels(t *testing.T) {