diff --git a/autoload/airline/section.vim b/autoload/airline/section.vim
index 788b443b..d14a828f 100644
--- a/autoload/airline/section.vim
+++ b/autoload/airline/section.vim
@@ -2,7 +2,6 @@
 " vim: et ts=2 sts=2 sw=2
 
 function! s:get_val(key, append)
-  let val = ''
   let part = airline#parts#get(a:key)
   if exists('part.function')
     let func = (part.function).'()'
@@ -14,12 +13,13 @@ function! s:get_val(key, append)
     return a:key
   endif
 
+  let val = ''
   if a:append > 0
     let val .= '%{airline#util#append('.func.')}'
   elseif a:append < 0
-    return '%{airline#util#prepend('.func.')}'
+    let val .= '%{airline#util#prepend('.func.')}'
   else
-    return '%{'.func.'}'
+    let val .= '%{'.func.'}'
   endif
   return val
 endfunction
diff --git a/t/parts.vim b/t/parts.vim
new file mode 100644
index 00000000..03fee1eb
--- /dev/null
+++ b/t/parts.vim
@@ -0,0 +1,24 @@
+describe 'parts'
+  it 'overwrites existing values'
+    call airline#parts#define('foo', { 'test': '123' })
+    Expect airline#parts#get('foo').test == '123'
+    call airline#parts#define('foo', { 'test': '321' })
+    Expect airline#parts#get('foo').test == '321'
+  end
+
+  it 'can define a function part'
+    call airline#parts#define_function('func', 'bar')
+    Expect airline#parts#get('func').function == 'bar'
+  end
+
+  it 'can define a text part'
+    call airline#parts#define_text('text', 'bar')
+    Expect airline#parts#get('text').text == 'bar'
+  end
+
+  it 'can define a raw part'
+    call airline#parts#define_raw('raw', 'bar')
+    Expect airline#parts#get('raw').raw == 'bar'
+  end
+end
+
diff --git a/t/section.vim b/t/section.vim
new file mode 100644
index 00000000..0a161054
--- /dev/null
+++ b/t/section.vim
@@ -0,0 +1,28 @@
+call airline#init#bootstrap()
+
+function! SectionSpec()
+endfunction
+
+describe 'section'
+  before
+    call airline#parts#define_text('text', 'text')
+    call airline#parts#define_raw('raw', 'raw')
+    call airline#parts#define_function('func', 'SectionSpec')
+  end
+
+  it 'should create sections with no separators'
+    let s = airline#section#create(['text', 'raw', 'func'])
+    Expect s == '%{"text"}raw%{SectionSpec()}'
+  end
+
+  it 'should create left sections with separators'
+    let s = airline#section#create_left(['text', 'text'])
+    Expect s == '%{"text"}%{airline#util#append("text")}'
+  end
+
+  it 'should create right sections with separators'
+    let s = airline#section#create_right(['text', 'text'])
+    Expect s == '%{airline#util#prepend("text")}%{"text"}'
+  end
+end
+