diff --git a/plugins/bak/bak.load b/plugins/bak/bak.load
index fd77967..a1e6a15 100644
--- a/plugins/bak/bak.load
+++ b/plugins/bak/bak.load
@@ -5,12 +5,10 @@ function __bak_help
 end
 
 function __bak_parse_help
-  function has_help_arg
-    # non implemented
-  end
-
-  if [ (count $argv) -lt 3 ]; or has_help_arg $argv
+  if [ (count $argv) -lt 3 ]
     __bak_help $argv[1]
+  else
+    return 1
   end
 end
 
diff --git a/plugins/bak/spec/bak.spec.fish b/plugins/bak/spec/bak.spec.fish
new file mode 100644
index 0000000..88af4e7
--- /dev/null
+++ b/plugins/bak/spec/bak.spec.fish
@@ -0,0 +1,111 @@
+import plugins/bak
+import plugins/fish-spec
+
+function describe_bak -d 'Testing bak plugin'
+  function before_all
+    set -g test_dir /tmp/bak_test
+    mkdir -p $test_dir
+    pushd
+    cd $test_dir
+    rm -rf $test_dir/*
+  end
+
+  function after_each
+    rm -rf $test_dir/*
+  end
+
+  function after_all
+    popd
+  end
+
+  function it_checks_bak_filename_pattern_is_followed
+    expect __is_bak '.ccnet.20140817_234302.bak' --to-be-true
+    expect __is_bak 'file\ with\ spaces.20140817_234302.bak' --to-be-true
+    expect __is_bak '.ccnet.bak' --to-be-false
+  end
+
+  function it_normalizes_file_name
+    expect (__bak_normalized '.ccnet.20140817_234302.bak') --to-equal '.ccnet'
+    expect (__bak_normalized 'file with spaces.20140817_234302.bak') --to-equal 'file with spaces'
+  end
+
+  function it_moves_a_single_file
+    touch a
+    mvbak a
+    expect __is_bak (ls) --to-be-true
+  end
+
+  function it_moves_multiple_files
+    touch a b
+    mvbak a b
+
+    for f in (ls)
+      expect __is_bak $f --to-be-true
+    end
+  end
+
+  function it_unmoves_a_single_file
+    touch a
+    mvbak a
+    unmvbak (ls)
+
+    expect (ls) --to-equal a
+  end
+
+  function it_unmoves_multiple_files
+    set files (seq 4)
+    touch $files
+    mvbak $files
+    unmvbak (ls)
+
+    expect (ls) --to-equal "$files"
+  end
+
+  function it_copies_a_single_file
+    touch a
+    cpbak a
+
+    expect (ls | sort) --to-equal (echo -e 'a' (__bak_name a) | sort)
+  end
+
+  function it_copies_multiple_files
+    set files (seq 4)
+    touch $files
+    cpbak $files
+
+    for f in $files
+      set files_bak $files_bak (__bak_name $f)
+    end
+
+    expect (ls | sort) --to-contain $files $file_bak
+  end
+
+  function it_uncopies_a_single_file
+    touch a
+    cpbak a
+    rm a
+    uncpbak (ls)
+
+    expect (ls | sort) --to-equal (echo -e 'a' (__bak_name a) | sort)
+  end
+
+  function it_uncopies_multiple_files
+    set files (seq 4)
+    touch $files
+    mvbak $files
+    unmvbak (ls)
+
+    expect (ls) --to-equal "$files"
+  end
+
+  function it_uncopies_a_directory
+    mkdir a
+    cpbak a/
+    rmdir a
+    uncpbak (ls -p)
+
+    expect (ls -p | sort) --to-equal (echo -e (__bak_name a)'/' 'a/')
+  end
+end
+
+spec.run $argv
diff --git a/plugins/bak/tests/helper.fish b/plugins/bak/tests/helper.fish
deleted file mode 100644
index e658e97..0000000
--- a/plugins/bak/tests/helper.fish
+++ /dev/null
@@ -1,8 +0,0 @@
-set -l fish_tank /usr/local/share/fish-tank/tank.fish
-if not test -e $fish_tank
-  echo 'error: fish-tank is required to run these tests (https://github.com/terlar/fish-tank)'
-  exit 1
-end
-
-source $fish_tank
-source (dirname (status -f))/../*.fish
diff --git a/plugins/bak/tests/test_bak.fish b/plugins/bak/tests/test_bak.fish
deleted file mode 100755
index abb4f1a..0000000
--- a/plugins/bak/tests/test_bak.fish
+++ /dev/null
@@ -1,110 +0,0 @@
-#!/usr/bin/env fish
-
-
-function suite_bak
-  function setup
-    return 0
-  end
-
-  function teardown
-    rm -rf $test_dir/*
-  end
-
-  function test_is_bak
-    assert (__is_bak '.ccnet.20140817_234302.bak')
-    assert (__is_bak 'file with spaces.20140817_234302.bak')
-    assert (not __is_bak '.ccnet.bak')
-  end
-
-  function test_normalized
-    assert_equal '.ccnet' (__bak_normalized '.ccnet.20140817_234302.bak')
-    assert_equal 'file with spaces' (__bak_normalized 'file with spaces.20140817_234302.bak')
-  end
-  
-  function test_mv_single
-    touch a
-    mvbak a
-    assert __is_bak (ls)
-  end
-
-  function test_mv_multiple
-    touch a b
-    mvbak a b
-    for f in (ls)
-      assert __is_bak $f
-    end
-  end
-
-  function test_unmv_single
-    touch a
-    mvbak a
-    unmvbak (ls)
-    assert_equal a (ls)
-  end
-
-  function test_unmv_multiple
-    set files (seq 4)
-    touch $files
-    mvbak $files
-    unmvbak (ls)
-    assert_equal "$files" (ls)
-  end
-
-  function test_cp_single
-    touch a
-    cpbak a
-    assert_equal (echo -e 'a' (__bak_name a) | sort) (ls | sort)
-  end
-
-  function test_cp_multiple
-    set files (seq 4)
-    touch $files
-    cpbak $files
-    for f in $files
-      set files_bak "$files_bak\n"(__bak_name $f) 
-    end
-    set expected (begin; echo $files | sed 's/ /\n/g'; echo -e $files_bak; end | sort | grep -v '^$')
-    assert_equal "$expected" (ls | sort)
-  end
-
-  function test_uncp_single
-    touch a
-    cpbak a
-    rm a
-    uncpbak (ls)
-    assert_equal (echo -e 'a' (__bak_name a) | sort) (ls | sort)
-  end
-
-  function test_uncp_dir_single
-    mkdir a
-    cpbak a/
-    rmdir a
-    uncpbak (ls -p)
-    assert_equal (echo -e 'a/' (__bak_name a)'/' | sort) (ls -p | sort)
-  end
-
-  function test_cp_multiple
-    set files (seq 4)
-    touch $files
-    cpbak $files
-    rm $files
-    uncpbak (ls)
-    for f in $files
-      set files_bak "$files_bak\n"(__bak_name $f) 
-    end
-    set expected (begin; echo $files | sed 's/ /\n/g'; echo -e $files_bak; end | sort | grep -v '^$')
-  end
-end
-
-if not set -q tank_running
-  source (dirname (status -f))/helper.fish
-
-  set -g test_dir /tmp/bak_test
-  mkdir -p $test_dir
-  pushd
-  cd $test_dir
-
-  tank_run
-
-  popd
-end