add cirrus freebsd test (#580)

For start cirrus please use:
https://cirrus-ci.org/guide/quick-start/
choose public repositories plan and add only xmobar as observed by cirrus.

Also here is addes small fix for dividing by zero when cpu usage is calculated

2 files changed, 49 insertions, 5 deletions

diff --git a/.cirrus.yml b/.cirrus.yml
new file mode 100644
index 0000000..6105386
--- /dev/null
+++ b/.cirrus.yml
@@ -0,0 +1,39 @@
+freebsd_instance:
+  image_family: freebsd-13-0
+
+build_task:
+  env:
+    CONFIG: "--enable-tests --enable-benchmarks -fwith_mpd -fwith_xft"
+
+  # caches the freebsd package downloads
+  # saves probably just a couple of seconds, but hey...
+  pkg_cache:
+    folder: /var/cache/pkg
+
+  install_script:
+    - pkg install -y ghc hs-hlint xorg-libraries hs-cabal-install git autoconf libmpdclient pkgconf libXft hs-hspec-discover
+
+  # cache the hackage index file and downloads which are
+  # cabal v2-update downloads an incremental update, so we don't need to keep this up2date
+  packages_cache:
+    # warning: don't use ~/.cabal here, this will break the cache
+    folder: /.cabal/packages
+    reupload_on_changes: false
+
+  # cache the dependencies built by cabal
+  # they have to be uploaded on every change to make the next build fast
+  store_cache:
+    # warning: don't use ~/.cabal here, this will break the cache
+    folder: /.cabal/store
+    fingerprint_script: cat xmobar.cabal
+    reupload_on_changes: true
+
+  build_script:
+    - cabal v2-update
+    - timeout 1800 cabal v2-build -j4 $CONFIG || (($?==124))
+
+  lint_script:
+    - hlint src
+
+  test_script:
+    - cabal v2-test -j4 $CONFIG
diff --git a/src/Xmobar/Plugins/Monitors/Cpu/FreeBSD.hs b/src/Xmobar/Plugins/Monitors/Cpu/FreeBSD.hs
index 7cb711a..7c80e55 100644
--- a/src/Xmobar/Plugins/Monitors/Cpu/FreeBSD.hs
+++ b/src/Xmobar/Plugins/Monitors/Cpu/FreeBSD.hs
@@ -39,11 +39,16 @@ parseCpu cref = do
         intr = diff !! 3
         idle = diff !! 4
         total = user + nice + system + intr + idle
+        cpuUserPerc = if total > 0 then user/total else 0
+        cpuNicePerc = if total > 0 then nice/total else 0
+        cpuSystemPerc = if total > 0 then (system+intr)/total else 0
+        cpuIdlePerc = if total > 0 then idle/total else 0
+
     return CpuData
-      { cpuUser = user/total
-      , cpuNice = nice/total
-      , cpuSystem = (system+intr)/total
-      , cpuIdle = idle/total
+      { cpuUser = cpuUserPerc
+      , cpuNice = cpuNicePerc
+      , cpuSystem = cpuSystemPerc
+      , cpuIdle = cpuIdlePerc
       , cpuIowait = 0
-      , cpuTotal = user/total
+      , cpuTotal = cpuUserPerc+cpuSystemPerc
       }