Try to fix time-sensitive tests in blockonkey.tcl

There is an inherent race between the deferring client and the
"main" client of the test: While the deferring client issues a blocking
command, we can't know for sure that by the time the "main" client
tries to issue another command (Usually one that unblocks the deferring
client) the deferring client is even blocked...
For lack of a better choice this commit uses TCL's 'after' in order
to give some time for the deferring client to issues its blocking
command before the "main" client does its thing.
This problem probably exists in many other tests but this commit
tries to fix blockonkeys.tcl

1 files changed, 54 insertions, 1 deletions

diff --git a/tests/unit/moduleapi/blockonkeys.tcl b/tests/unit/moduleapi/blockonkeys.tcl
index c8b8f23ed..5e5d93da3 100644
--- a/tests/unit/moduleapi/blockonkeys.tcl
+++ b/tests/unit/moduleapi/blockonkeys.tcl
@@ -11,6 +11,12 @@ start_server {tags {"modules"}} {
 
         $rd1 fsl.bpoppush src dst 0
         $rd2 fsl.bpoppush dst src 0
+        ;# wait until clients are actually blocked
+        wait_for_condition 50 100 {
+            [s 0 blocked_clients] eq {2}
+        } else {
+            fail "Clients are not blocked"
+        }
 
         r fsl.push src 42
 
@@ -24,7 +30,12 @@ start_server {tags {"modules"}} {
         r del src
 
         $rd1 fsl.bpoppush src src 0
-
+        ;# wait until clients are actually blocked
+        wait_for_condition 50 100 {
+            [s 0 blocked_clients] eq {1}
+        } else {
+            fail "Clients are not blocked"
+        }
         r fsl.push src 42
 
         assert_equal {42} [r fsl.getall src]
@@ -48,6 +59,12 @@ start_server {tags {"modules"}} {
         r del k
         set rd [redis_deferring_client]
         $rd fsl.bpop k 0
+        ;# wait until clients are actually blocked
+        wait_for_condition 50 100 {
+            [s 0 blocked_clients] eq {1}
+        } else {
+            fail "Clients are not blocked"
+        }
         r fsl.push k 34
         assert_equal {34} [$rd read]
     }
@@ -76,6 +93,12 @@ start_server {tags {"modules"}} {
         set cid [$rd read]
         r fsl.push k 33
         $rd fsl.bpopgt k 33 0
+        ;# wait until clients are actually blocked
+        wait_for_condition 50 100 {
+            [s 0 blocked_clients] eq {1}
+        } else {
+            fail "Clients are not blocked"
+        }
         r fsl.push k 34
         assert_equal {34} [$rd read]
         r client kill id $cid ;# try to smoke-out client-related memory leak
@@ -85,6 +108,12 @@ start_server {tags {"modules"}} {
         r del k
         set rd [redis_deferring_client]
         $rd fsl.bpopgt k 35 0
+        ;# wait until clients are actually blocked
+        wait_for_condition 50 100 {
+            [s 0 blocked_clients] eq {1}
+        } else {
+            fail "Clients are not blocked"
+        }
         r fsl.push k 33
         r fsl.push k 34
         r fsl.push k 35
@@ -98,6 +127,12 @@ start_server {tags {"modules"}} {
         $rd client id
         set cid [$rd read]
         $rd fsl.bpopgt k 35 0
+        ;# wait until clients are actually blocked
+        wait_for_condition 50 100 {
+            [s 0 blocked_clients] eq {1}
+        } else {
+            fail "Clients are not blocked"
+        }
         r client kill id $cid ;# try to smoke-out client-related memory leak
     }
 
@@ -107,6 +142,12 @@ start_server {tags {"modules"}} {
         $rd client id
         set cid [$rd read]
         $rd fsl.bpopgt k 35 0
+        ;# wait until clients are actually blocked
+        wait_for_condition 50 100 {
+            [s 0 blocked_clients] eq {1}
+        } else {
+            fail "Clients are not blocked"
+        }
         r client unblock $cid timeout ;# try to smoke-out client-related memory leak
         assert_equal {Request timedout} [$rd read]
     }
@@ -117,6 +158,12 @@ start_server {tags {"modules"}} {
         $rd client id
         set cid [$rd read]
         $rd fsl.bpopgt k 35 0
+        ;# wait until clients are actually blocked
+        wait_for_condition 50 100 {
+            [s 0 blocked_clients] eq {1}
+        } else {
+            fail "Clients are not blocked"
+        }
         r client unblock $cid error ;# try to smoke-out client-related memory leak
         assert_error "*unblocked*" {$rd read}
     }
@@ -125,6 +172,12 @@ start_server {tags {"modules"}} {
         r del k
         set rd [redis_deferring_client]
         $rd fsl.bpop k 0
+        ;# wait until clients are actually blocked
+        wait_for_condition 50 100 {
+            [s 0 blocked_clients] eq {1}
+        } else {
+            fail "Clients are not blocked"
+        }
         r lpush k 12
         r lpush k 13
         r lpush k 14