t: cover flux kvs sync

Problem: The new flux kvs sync command is not covered.

Add coverage in t1010-kvs-commit-sync.t.

Author: chu11

t/t1010-kvs-commit-sync.t

@@ -33,7 +33,7 @@ test_expect_success 'kvs: no checkpoint of kvs-primary should exist yet' '
         test_must_fail checkpoint_get kvs-primary
 '
 
-test_expect_success 'kvs: put some data to kvs and sync it' '
+test_expect_success 'kvs: put some data to kvs and sync it (flux kvs put)' '
         flux kvs put --blobref --sync c=3 > syncblob.out
 '
 
@@ -46,6 +46,16 @@ test_expect_success 'kvs: checkpoint of kvs-primary should match rootref' '
         test_cmp syncblob.out checkpoint.out
 '
 
+test_expect_success 'kvs: put some data to kvs and sync it (flux kvs sync)' '
+        flux kvs put --blobref d=4 > syncblob2.out &&
+        flux kvs sync
+'
+
+test_expect_success 'kvs: checkpoint of kvs-primary should match rootref' '
+        checkpoint_get kvs-primary | jq -r .value.rootref > checkpoint2.out &&
+        test_cmp syncblob2.out checkpoint2.out
+'
+
 test_expect_success 'kvs: sync fails against non-primary namespace' '
         flux kvs namespace create ${TESTNAMESPACE} &&
         flux kvs put --namespace=${TESTNAMESPACE} a=10 &&