e2e/ctl_v3_alarm_test: Fix quota test

Rework the over quota test to be more a realistic test.  Take into
consideration that the system page size will be different across
platforms.

Signed-off-by: Geoff Levand <geoff@infradead.org>

e2e/ctl_v3_alarm_test.go

@@ -15,44 +15,62 @@
 package e2e
 
 import (
+	"os"
 	"strings"
 	"testing"
 )
 
-func TestCtlV3Alarm(t *testing.T) { testCtl(t, alarmTest, withQuota(64*1024)) }
+func TestCtlV3Alarm(t *testing.T) {
+	// The boltdb minimum working set is six pages.
+	testCtl(t, alarmTest, withQuota(int64(13*os.Getpagesize())))
+}
 
 func alarmTest(cx ctlCtx) {
 	// test small put still works
 	smallbuf := strings.Repeat("a", 64)
-	if err := ctlV3Put(cx, "abc", smallbuf, ""); err != nil {
+	if err := ctlV3Put(cx, "1st_test", smallbuf, ""); err != nil {
 		cx.t.Fatal(err)
 	}
 
-	// test big put (to be rejected, and trigger quota alarm)
-	bigbuf := strings.Repeat("a", int(cx.quotaBackendBytes))
-	if err := ctlV3Put(cx, "abc", bigbuf, ""); err != nil {
-		if !strings.Contains(err.Error(), "etcdserver: mvcc: database space exceeded") {
-			cx.t.Fatal(err)
+	// write some chunks to fill up the database
+	buf := strings.Repeat("b", int(os.Getpagesize()))
+	var rev int64
+	for ; ; rev++ {
+		if err := ctlV3Put(cx, "2nd_test", buf, ""); err != nil {
+			if !strings.Contains(err.Error(), "etcdserver: mvcc: database space exceeded") {
+				cx.t.Fatal(err)
+			}
+			break
 		}
 	}
+
+	// quota alarm should now be on
 	if err := ctlV3Alarm(cx, "list", "alarm:NOSPACE"); err != nil {
 		cx.t.Fatal(err)
 	}
 
-	// alarm is on rejecting Puts and Txns
-	if err := ctlV3Put(cx, "def", smallbuf, ""); err != nil {
+	// check that Put is rejected when alarm is on
+	if err := ctlV3Put(cx, "3rd_test", smallbuf, ""); err != nil {
 		if !strings.Contains(err.Error(), "etcdserver: mvcc: database space exceeded") {
 			cx.t.Fatal(err)
 		}
 	}
 
+	// make some space
+	if err := ctlV3Compact(cx, rev, true); err != nil {
+		cx.t.Fatal(err)
+	}
+	if err := ctlV3Defrag(cx); err != nil {
+		cx.t.Fatal(err)
+	}
+
 	// turn off alarm
 	if err := ctlV3Alarm(cx, "disarm", "alarm:NOSPACE"); err != nil {
 		cx.t.Fatal(err)
 	}
 
 	// put one more key below quota
-	if err := ctlV3Put(cx, "ghi", smallbuf, ""); err != nil {
+	if err := ctlV3Put(cx, "4th_test", smallbuf, ""); err != nil {
 		cx.t.Fatal(err)
 	}
 }