change cwd for less and sass compiler

pipeline/compilers/__init__.py

@@ -68,9 +68,10 @@ class CompilerError(Exception):
 
 
 class SubProcessCompiler(CompilerBase):
-    def execute_command(self, command, content=None):
-        pipe = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE,
-            stdin=subprocess.PIPE, stderr=subprocess.PIPE)
+    def execute_command(self, command, content=None, cwd=None):
+        pipe = subprocess.Popen(command, shell=True, cwd=cwd,
+            stdout=subprocess.PIPE, stdin=subprocess.PIPE,
+            stderr=subprocess.PIPE)
 
         if content:
             pipe.stdin.write(content)

pipeline/compilers/less/__init__.py

+import os.path
+
 from pipeline.conf import settings
 from pipeline.compilers import SubProcessCompiler
 
@@ -14,5 +16,6 @@ class LessCompiler(SubProcessCompiler):
             settings.PIPELINE_LESS_ARGUMENTS,
             path
         )
-        content = self.execute_command(command)
+        cwd = os.path.dirname(path)
+        content = self.execute_command(command, cwd=cwd)
         return content

pipeline/compilers/sass/__init__.py

+import os.path
+
 from pipeline.conf import settings
 from pipeline.compilers import SubProcessCompiler
 
@@ -14,4 +16,5 @@ class SASSCompiler(SubProcessCompiler):
             settings.PIPELINE_SASS_ARGUMENTS,
             path
         )
-        return self.execute_command(command)
+        cwd = os.path.dirname(path)
+        return self.execute_command(command, cwd=cwd)