fix: add unit tests for error classification

Author: aaaTurbo

collector/nginx_test.go

@@ -0,0 +1,129 @@
+package collector
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+func TestIsNetworkError(t *testing.T) {
+	tests := []struct {
+		name     string
+		errorMsg string
+		want     bool
+	}{
+		{
+			name:     "network connection error",
+			errorMsg: "failed to get http://localhost:8080/stub_status: connection refused",
+			want:     true,
+		},
+		{
+			name:     "network timeout error",
+			errorMsg: "failed to get http://localhost:8080/stub_status: timeout",
+			want:     true,
+		},
+		{
+			name:     "HTTP error",
+			errorMsg: "expected 200 response, got 404",
+			want:     false,
+		},
+		{
+			name:     "parse error",
+			errorMsg: "failed to parse response body",
+			want:     false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := isNetworkError(tt.errorMsg); got != tt.want {
+				t.Errorf("isNetworkError() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestIsHTTPError(t *testing.T) {
+	tests := []struct {
+		name     string
+		errorMsg string
+		want     bool
+	}{
+		{
+			name:     "HTTP 404 error",
+			errorMsg: "expected 200 response, got 404",
+			want:     true,
+		},
+		{
+			name:     "HTTP 500 error",
+			errorMsg: "expected 200 response, got 500",
+			want:     true,
+		},
+		{
+			name:     "network error",
+			errorMsg: "failed to get http://localhost:8080/stub_status: connection refused",
+			want:     false,
+		},
+		{
+			name:     "parse error",
+			errorMsg: "failed to parse response body",
+			want:     false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := isHTTPError(tt.errorMsg); got != tt.want {
+				t.Errorf("isHTTPError() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestNewScrapeSuccessMetric(t *testing.T) {
+	metric := newScrapeSuccessMetric("nginx", map[string]string{"job": "nginx"})
+
+	if metric == nil {
+		t.Error("newScrapeSuccessMetric() returned nil")
+	}
+
+	desc := metric.Desc().String()
+	if !strings.Contains(desc, "nginx_scrape_success") {
+		t.Errorf("metric description should contain 'nginx_scrape_success', got: %s", desc)
+	}
+}
+
+func TestNewScrapeDurationMetric(t *testing.T) {
+	metric := newScrapeDurationMetric("nginx", map[string]string{"job": "nginx"})
+
+	if metric == nil {
+		t.Error("newScrapeDurationMetric() returned nil")
+	}
+
+	desc := metric.Desc().String()
+	if !strings.Contains(desc, "nginx_scrape_duration_seconds") {
+		t.Errorf("metric description should contain 'nginx_scrape_duration_seconds', got: %s", desc)
+	}
+}
+
+func TestNewScrapeErrorsTotalMetric(t *testing.T) {
+	metric := newScrapeErrorsTotalMetric("nginx", map[string]string{"job": "nginx"})
+
+	if metric == nil {
+		t.Error("newScrapeErrorsTotalMetric() returned nil")
+	}
+
+	ch := make(chan *prometheus.Desc, 10)
+	metric.Describe(ch)
+	close(ch)
+
+	count := 0
+	for range ch {
+		count++
+	}
+
+	if count == 0 {
+		t.Error("metric should have descriptions")
+	}
+}