tests: new file test_helper_libs.bash

For testing non-core files, just `load ../test_helper_libs` after `load ../test_helper` instead of trying to guess which libs must be loaded, in which order, for testing to succeed.

`_command_exists` spews log messages, so our test log is littered with `_log_debug not found`. This fixes that too.

test/plugins/alias-completion.plugin.bats

@@ -1,8 +1,7 @@
 #!/usr/bin/env bats
 
 load ../test_helper
-load ../../lib/log
-load ../../lib/helpers
+load ../test_helper_libs
 
 load ../../completion/available/capistrano.completion
 

test/plugins/base.plugin.bats

@@ -1,8 +1,7 @@
 #!/usr/bin/env bats
 
 load ../test_helper
-load ../../lib/log
-load ../../lib/helpers
+load ../test_helper_libs
 load ../../plugins/available/base.plugin
 
 @test 'plugins base: ips()' {

test/plugins/battery.plugin.bats

@@ -1,8 +1,7 @@
 #!/usr/bin/env bats
 
 load ../test_helper
-load "${BASH_IT}/lib/log.bash"
-load "${BASH_IT}/lib/helpers.bash"
+load ../test_helper_libs
 
 load ../../plugins/available/battery.plugin
 

test/plugins/cmd-returned-notify.plugin.bats

@@ -1,7 +1,7 @@
 #!/usr/bin/env bats
 
 load ../test_helper
-load ../../lib/helpers
+load ../test_helper_libs
 load ../../vendor/init.d/preexec
 
 load ../../plugins/available/cmd-returned-notify.plugin

test/plugins/go.plugin.bats

@@ -1,7 +1,7 @@
 #!/usr/bin/env bats
 
 load ../test_helper
-load ../../lib/helpers
+load ../test_helper_libs
 
 # We test `go version` in each test to account for users with goenv and no system go.
 

test/plugins/ruby.plugin.bats

@@ -1,7 +1,7 @@
 #!/usr/bin/env bats
 
 load ../test_helper
-load ../../lib/helpers
+load ../test_helper_libs
 
 function local_setup {
   setup_test_fixture

test/plugins/xterm.plugin.bats

@@ -1,8 +1,7 @@
 #!/usr/bin/env bats
 
 load ../test_helper
-load ../../lib/log
-load ../../lib/helpers
+load ../test_helper_libs
 
 load ../../plugins/available/xterm.plugin