fix(tests): more test coverage

cmd/karma/main.go

@@ -61,7 +61,14 @@ func getViewURL(sub string) string {
 	if !strings.HasPrefix(sub, "/") {
 		fixedSub = "/" + sub
 	}
-	u := path.Join(config.Config.Listen.Prefix, fixedSub)
+
+	var fixedPrefix string
+	fixedPrefix = config.Config.Listen.Prefix
+	if config.Config.Listen.Prefix != "" && !strings.HasPrefix(config.Config.Listen.Prefix, "/") {
+		fixedPrefix = "/" + config.Config.Listen.Prefix
+	}
+
+	u := path.Join(fixedPrefix, fixedSub)
 	if strings.HasSuffix(fixedSub, "/") && !strings.HasSuffix(u, "/") {
 		// if sub path had trailing slash then add it here, since path.Join will
 		// skip it

cmd/karma/main_test.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"net/http"
 	"net/http/httptest"
 	"strings"
@@ -45,7 +46,6 @@ func TestMetrics(t *testing.T) {
 	}
 	body := resp.Body.String()
 	for _, s := range []string{
-		"karma_collected_alerts_count",
 		"karma_collected_alerts_count",
 		"karma_collect_cycles_total",
 		"karma_alertmanager_errors_total",
@@ -55,3 +55,68 @@ func TestMetrics(t *testing.T) {
 		}
 	}
 }
+
+func TestGetViewURL(t *testing.T) {
+	type testCaseT struct {
+		prefix string
+		view   string
+		result string
+	}
+	tests := []testCaseT{
+		{
+			prefix: "",
+			view:   "/",
+			result: "/",
+		},
+		{
+			prefix: "",
+			view:   "foo",
+			result: "/foo",
+		},
+		{
+			prefix: "root",
+			view:   "foo",
+			result: "/root/foo",
+		},
+		{
+			prefix: "root",
+			view:   "foo/",
+			result: "/root/foo/",
+		},
+		{
+			prefix: "/root",
+			view:   "foo",
+			result: "/root/foo",
+		},
+		{
+			prefix: "root/",
+			view:   "foo",
+			result: "/root/foo",
+		},
+		{
+			prefix: "root/",
+			view:   "foo/",
+			result: "/root/foo/",
+		},
+		{
+			prefix: "/root/",
+			view:   "foo",
+			result: "/root/foo",
+		},
+		{
+			prefix: "/root/",
+			view:   "/foo/",
+			result: "/root/foo/",
+		},
+	}
+
+	for _, testCase := range tests {
+		t.Run(fmt.Sprintf("prefix=%q view=%v result=%q", testCase.prefix, testCase.view, testCase.result), func(t *testing.T) {
+			config.Config.Listen.Prefix = testCase.prefix
+			result := getViewURL(testCase.view)
+			if result != testCase.result {
+				t.Errorf("getViewURL(%s) returned %q, expected %q", testCase.view, result, testCase.result)
+			}
+		})
+	}
+}

cmd/karma/proxy_test.go

@@ -103,6 +103,8 @@ func TestProxy(t *testing.T) {
 	"matchers": [{ "isRegex": false, "name": "alertname", "value": "Fake Alert" }]
 }`
 
+	config.Config.Listen.Prefix = ""
+
 	r := ginTestEngine()
 	am, err := alertmanager.NewAlertmanager(
 		"cluster",