Update test cases for cachereadahead greater than zero

Signed-off-by: Saleh Sal <0xack13@gmail.com>

collector/fixtures/e2e-64k-page-output.txt

@@ -95,6 +95,9 @@ node_bcache_cache_misses_total{backing_device="bdev0",uuid="deaddd54-c735-46d5-8
 # HELP node_bcache_cache_read_races_total Counts instances where while data was being read from the cache, the bucket was reused and invalidated - i.e. where the pointer was stale after the read completed.
 # TYPE node_bcache_cache_read_races_total counter
 node_bcache_cache_read_races_total{uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 0
+# HELP node_bcache_cache_readaheads_total Count of times readahead occurred.
+# TYPE node_bcache_cache_readaheads_total counter
+node_bcache_cache_readaheads_total{backing_device="bdev0",uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 13
 # HELP node_bcache_congested Congestion.
 # TYPE node_bcache_congested gauge
 node_bcache_congested{uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 0

collector/fixtures/e2e-output.txt

@@ -95,6 +95,9 @@ node_bcache_cache_misses_total{backing_device="bdev0",uuid="deaddd54-c735-46d5-8
 # HELP node_bcache_cache_read_races_total Counts instances where while data was being read from the cache, the bucket was reused and invalidated - i.e. where the pointer was stale after the read completed.
 # TYPE node_bcache_cache_read_races_total counter
 node_bcache_cache_read_races_total{uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 0
+# HELP node_bcache_cache_readaheads_total Count of times readahead occurred.
+# TYPE node_bcache_cache_readaheads_total counter
+node_bcache_cache_readaheads_total{backing_device="bdev0",uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 13
 # HELP node_bcache_congested Congestion.
 # TYPE node_bcache_congested gauge
 node_bcache_congested{uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 0

collector/fixtures/sys.ttar

@@ -2394,6 +2394,11 @@ Lines: 1
 0
 Mode: 644
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: sys/devices/pci0000:00/0000:00:0d.0/ata4/host3/target3:0:0/3:0:0:0/block/sdb/bcache/stats_day/cache_readaheads
+Lines: 1
+13
+Mode: 644
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Directory: sys/devices/pci0000:00/0000:00:0d.0/ata4/host3/target3:0:0/3:0:0:0/block/sdb/bcache/stats_five_minute
 Mode: 755
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -2432,6 +2437,11 @@ Lines: 1
 0
 Mode: 644
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: sys/devices/pci0000:00/0000:00:0d.0/ata4/host3/target3:0:0/3:0:0:0/block/sdb/bcache/stats_five_minute/cache_readaheads
+Lines: 1
+13
+Mode: 644
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Directory: sys/devices/pci0000:00/0000:00:0d.0/ata4/host3/target3:0:0/3:0:0:0/block/sdb/bcache/stats_hour
 Mode: 755
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -2470,6 +2480,11 @@ Lines: 1
 0
 Mode: 644
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: sys/devices/pci0000:00/0000:00:0d.0/ata4/host3/target3:0:0/3:0:0:0/block/sdb/bcache/stats_hour/cache_readaheads
+Lines: 1
+13
+Mode: 644
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Directory: sys/devices/pci0000:00/0000:00:0d.0/ata4/host3/target3:0:0/3:0:0:0/block/sdb/bcache/stats_total
 Mode: 755
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -2508,6 +2523,11 @@ Lines: 1
 0
 Mode: 644
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: sys/devices/pci0000:00/0000:00:0d.0/ata4/host3/target3:0:0/3:0:0:0/block/sdb/bcache/stats_total/cache_readaheads
+Lines: 1
+13
+Mode: 644
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Path: sys/devices/pci0000:00/0000:00:0d.0/ata4/host3/target3:0:0/3:0:0:0/block/sdb/bcache/writeback_rate_debug
 Lines: 7
 rate:           1.1M/sec
@@ -3878,6 +3898,11 @@ Lines: 1
 0
 Mode: 644
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: sys/fs/bcache/deaddd54-c735-46d5-868e-f331c5fd7c74/stats_day/cache_readaheads
+Lines: 1
+13
+Mode: 644
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Directory: sys/fs/bcache/deaddd54-c735-46d5-868e-f331c5fd7c74/stats_five_minute
 Mode: 755
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -3916,6 +3941,11 @@ Lines: 1
 0
 Mode: 644
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: sys/fs/bcache/deaddd54-c735-46d5-868e-f331c5fd7c74/stats_five_minute/cache_readaheads
+Lines: 1
+13
+Mode: 644
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Directory: sys/fs/bcache/deaddd54-c735-46d5-868e-f331c5fd7c74/stats_hour
 Mode: 755
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -3954,6 +3984,11 @@ Lines: 1
 0
 Mode: 644
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: sys/fs/bcache/deaddd54-c735-46d5-868e-f331c5fd7c74/stats_hour/cache_readaheads
+Lines: 1
+13
+Mode: 644
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Directory: sys/fs/bcache/deaddd54-c735-46d5-868e-f331c5fd7c74/stats_total
 Mode: 755
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -3992,6 +4027,11 @@ Lines: 1
 0
 Mode: 644
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: sys/fs/bcache/deaddd54-c735-46d5-868e-f331c5fd7c74/stats_total/cache_readaheads
+Lines: 1
+13
+Mode: 644
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Path: sys/fs/bcache/deaddd54-c735-46d5-868e-f331c5fd7c74/tree_depth
 Lines: 1
 0