Prepare tests for performance optimizations

test/segments/php_version.spec

@@ -7,8 +7,6 @@ SHUNIT_PARENT=$0
 
 function setUp() {
   export TERM="xterm-256color"
-  # Load Powerlevel9k
-  source powerlevel9k.zsh-theme
 }
 
 function testPhpVersionSegmentPrintsNothingIfPhpIsNotAvailable() {
@@ -17,6 +15,9 @@ function testPhpVersionSegmentPrintsNothingIfPhpIsNotAvailable() {
   local POWERLEVEL9K_CUSTOM_WORLD='echo world'
   alias php="nophp"
 
+  # Load Powerlevel9k
+  source powerlevel9k.zsh-theme
+
   assertEquals "%K{white} %F{black}world %k%F{white}%f " "$(build_left_prompt)"
 
   unalias php
@@ -30,6 +31,9 @@ Copyright (c) 1997-2016 The PHP Group
 Zend Engine v2.6.0, Copyright (c) 1998-2016 Zend Technologies
 '"
 
+  # Load Powerlevel9k
+  source powerlevel9k.zsh-theme
+
   assertEquals "%K{013} %F{255}PHP 5.6.27 %k%F{fuchsia}%f " "$(build_left_prompt)"
 
   unalias php