Move formatAndClearCountryStats test into a new metrics_test.go.

This is more unit test–y. We don't need a full broker instantiation for
testing this function, unlike other tests in snowflake-broker_test.go.

broker/metrics_test.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"sync"
+	"sync/atomic"
+	"testing"
+
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestFormatAndClearCountryStats(t *testing.T) {
+	Convey("for country stats order", t, func() {
+		stats := new(sync.Map)
+		for cc, count := range map[string]uint64{
+			"IT": 50,
+			"FR": 200,
+			"TZ": 100,
+			"CN": 250,
+			"RU": 150,
+			"CA": 1,
+			"BE": 1,
+			"PH": 1,
+		} {
+			stats.LoadOrStore(cc, new(uint64))
+			val, _ := stats.Load(cc)
+			ptr := val.(*uint64)
+			atomic.AddUint64(ptr, count)
+		}
+		So(formatAndClearCountryStats(stats, false), ShouldEqual, "CN=250,FR=200,RU=150,TZ=100,IT=50,BE=1,CA=1,PH=1")
+		// The map should be cleared on return.
+		stats.Range(func(_, _ any) bool { panic("map was not cleared") })
+	})
+}

broker/snowflake-broker_test.go

@@ -11,7 +11,6 @@ import (
 	"net/http/httptest"
 	"os"
 	"sync"
-	"sync/atomic"
 	"testing"
 	"time"
 
@@ -1030,26 +1029,5 @@ snowflake-ips-nat-unknown 0
 			ctx.metrics.printMetrics()
 			So(buf.String(), ShouldContainSubstring, "client-denied-count 8\nclient-restricted-denied-count 8\nclient-unrestricted-denied-count 0\nclient-snowflake-match-count 0")
 		})
-		Convey("for country stats order", func() {
-			stats := new(sync.Map)
-			for cc, count := range map[string]uint64{
-				"IT": 50,
-				"FR": 200,
-				"TZ": 100,
-				"CN": 250,
-				"RU": 150,
-				"CA": 1,
-				"BE": 1,
-				"PH": 1,
-			} {
-				stats.LoadOrStore(cc, new(uint64))
-				val, _ := stats.Load(cc)
-				ptr := val.(*uint64)
-				atomic.AddUint64(ptr, count)
-			}
-			So(formatAndClearCountryStats(stats, false), ShouldEqual, "CN=250,FR=200,RU=150,TZ=100,IT=50,BE=1,CA=1,PH=1")
-			// The map should be cleared on return.
-			stats.Range(func(_, _ any) bool { panic("map was not cleared") })
-		})
 	})
 }