Sentinel test: add manual failover test.

tests/sentinel/tests/05-manual.tcl

+# Test manual failover
+
+source "../tests/includes/init-tests.tcl"
+
+test "Manual failover works" {
+    set old_port [RI $master_id tcp_port]
+    set addr [S 0 SENTINEL GET-MASTER-ADDR-BY-NAME mymaster]
+    assert {[lindex $addr 1] == $old_port}
+    S 0 SENTINEL FAILOVER mymaster
+    foreach_sentinel_id id {
+        wait_for_condition 1000 50 {
+            [lindex [S $id SENTINEL GET-MASTER-ADDR-BY-NAME mymaster] 1] != $old_port
+        } else {
+            fail "At least one Sentinel did not received failover info"
+        }
+    }
+    set addr [S 0 SENTINEL GET-MASTER-ADDR-BY-NAME mymaster]
+    set master_id [get_instance_id_by_port redis [lindex $addr 1]]
+}
+
+test "New master [join $addr {:}] role matches" {
+    assert {[RI $master_id role] eq {master}}
+}
+
+test "All the other slaves now point to the new master" {
+    foreach_redis_id id {
+        if {$id != $master_id && $id != 0} {
+            wait_for_condition 1000 50 {
+                [RI $id master_port] == [lindex $addr 1]
+            } else {
+                fail "Redis ID $id not configured to replicate with new master"
+            }
+        }
+    }
+}
+
+test "The old master eventually gets reconfigured as a slave" {
+    wait_for_condition 1000 50 {
+        [RI 0 master_port] == [lindex $addr 1]
+    } else {
+        fail "Old master not reconfigured as slave of new master"
+    }
+}
+