test: add unit tests for IsPingEntryPoint

Covers nil receiver, nil ping config, matching entry point,
non-matching entry point, and unrelated entry point on the
same instance.

pkg/server/middleware/observability_test.go

@@ -0,0 +1,69 @@
+package middleware
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/traefik/traefik/v3/pkg/config/static"
+	"github.com/traefik/traefik/v3/pkg/ping"
+)
+
+func TestIsPingEntryPoint(t *testing.T) {
+	testCases := []struct {
+		desc           string
+		mgr            *ObservabilityMgr
+		entryPointName string
+		expected       bool
+	}{
+		{
+			desc:           "nil ObservabilityMgr receiver",
+			mgr:            nil,
+			entryPointName: "websecure",
+			expected:       false,
+		},
+		{
+			desc:           "ping config is nil",
+			mgr:            &ObservabilityMgr{config: static.Configuration{}},
+			entryPointName: "websecure",
+			expected:       false,
+		},
+		{
+			desc: "entry point matches configured ping entry point",
+			mgr: &ObservabilityMgr{
+				config: static.Configuration{
+					Ping: &ping.Handler{EntryPoint: "websecure"},
+				},
+			},
+			entryPointName: "websecure",
+			expected:       true,
+		},
+		{
+			desc: "entry point does not match configured ping entry point",
+			mgr: &ObservabilityMgr{
+				config: static.Configuration{
+					Ping: &ping.Handler{EntryPoint: "websecure"},
+				},
+			},
+			entryPointName: "web",
+			expected:       false,
+		},
+		{
+			desc: "non-ping entry point on same traefik instance",
+			mgr: &ObservabilityMgr{
+				config: static.Configuration{
+					Ping: &ping.Handler{EntryPoint: "ping"},
+				},
+			},
+			entryPointName: "websecure",
+			expected:       false,
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			assert.Equal(t, test.expected, test.mgr.IsPingEntryPoint(test.entryPointName))
+		})
+	}
+}