diff --git a/lesscpy/lessc/lexer.py b/lesscpy/lessc/lexer.py
index a333d94..97b574e 100644
--- a/lesscpy/lessc/lexer.py
+++ b/lesscpy/lessc/lexer.py
@@ -11,6 +11,7 @@
 """
 import re
 import ply.lex as lex
+from six import string_types
 
 from lesscpy.lib import dom
 from lesscpy.lib import css
@@ -460,12 +461,16 @@ class LessLexer:
             self.lexer.input(f.read())
         return self
 
-    def input(self, filename):
+    def input(self, file):
         """
-        Wrapper for file
+        Load lexer with content from `file` which can be a path or a file
+        like object.
         """
-        with open(filename) as f:
-            self.lexer.input(f.read())
+        if isinstance(file, string_types):
+            with open(file) as f:
+                self.lexer.input(f.read())
+        else:
+            self.lexer.input(file.read())
 
     def token(self):
         """
diff --git a/lesscpy/lessc/parser.py b/lesscpy/lessc/parser.py
index 153feff..32014c3 100644
--- a/lesscpy/lessc/parser.py
+++ b/lesscpy/lessc/parser.py
@@ -77,18 +77,33 @@ class LessParser(object):
         self.result = None
         self.target = None
 
-    def parse(self, filename='', debuglevel=0):
+    def parse(self, filename=None, file=None, debuglevel=0):
         """ Parse file.
         kwargs:
             filename (str): File to parse
             debuglevel (int): Parser debuglevel
         """
+        self.scope.push()
+
+        if not file:
+            # We use a path.
+            file = filename
+        else:
+            # We use a stream and try to extract the name from the stream.
+            if hasattr(file, 'name'):
+                if filename is not None:
+                    raise AssertionError(
+                        'names of file and filename are in conflict')
+                filename = file.name()
+            else:
+                filename = '(stream)'
+
+        self.target = filename
         if self.verbose:
             print('Compiling target: %s' % filename, file=sys.stderr)
-        self.scope.push()
-        self.target = filename
         self.result = self.parser.parse(
-            filename, lexer=self.lex, debug=debuglevel)
+            file, lexer=self.lex, debug=debuglevel)
+
         self.post_parse()
 
     def post_parse(self):
diff --git a/requirements.txt b/requirements.txt
index 90412f0..4efa1dc 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1 +1,2 @@
 ply
+six
diff --git a/test/test_lexer.py b/test/test_lexer.py
new file mode 100644
index 0000000..60b573b
--- /dev/null
+++ b/test/test_lexer.py
@@ -0,0 +1,47 @@
+"""
+Unit tests for the lexer.
+"""
+from tempfile import NamedTemporaryFile
+import unittest
+
+from six import StringIO
+
+from lesscpy.lessc.lexer import LessLexer
+
+
+class TestLessLexer(unittest.TestCase):
+    """
+    Unit tests for LessLexer
+    """
+
+    def setUp(self):
+        self.lexer = LessLexer()
+
+
+    def test_input_stream(self):
+        """
+        It can load content from a string.
+        """
+        file = StringIO("""
+            @simple-var: 1;
+            """)
+
+        self.lexer.input(file)
+
+        token = self.lexer.token()
+        self.assertEqual('@simple-var', token.value)
+
+    def test_input_path(self):
+        """
+        It can load content from a path.
+        """
+        file = NamedTemporaryFile()
+        file.write(b"""
+            @simple-var: 1;
+            """)
+        file.seek(0)
+
+        self.lexer.input(file.name)
+
+        token = self.lexer.token()
+        self.assertEqual('@simple-var', token.value)
diff --git a/test/test_parser.py b/test/test_parser.py
new file mode 100644
index 0000000..7a23605
--- /dev/null
+++ b/test/test_parser.py
@@ -0,0 +1,35 @@
+"""
+Unit test for the parser.
+"""
+import unittest
+
+from six import StringIO
+
+from lesscpy.lessc.parser import LessParser
+
+
+class TestLessParser(unittest.TestCase):
+    """
+    Unit tests for LessParser.
+    """
+
+    def setUp(self):
+        self.parser = LessParser()
+
+    def test_parse_stream(self):
+        """
+        It can parse input from a file stream.
+        """
+        stream = StringIO("""
+            @nice-blue: #5B83AD;
+            """)
+
+        self.parser.parse(file=stream)
+
+        # A single object is parser which is the expected variable.
+        self.assertEqual(1, len(self.parser.result))
+        # This is a stream without a name so it sets default name.
+        self.assertEqual('(stream)', self.parser.target)
+        variable = self.parser.result[0]
+        self.assertEqual('@nice-blue', variable.name)
+        self.assertEqual(['#5b83ad'], variable.value)