Add more tests for at method. Fix bug. Update CHANGELOG and documentation.

CHANGELOG

@@ -4,6 +4,7 @@ Changelog
 0.6.2 (unreleased)
 ----------------
+- add at method
 - fix some old call to log() weren't lazy, that could cause a crash in some situations by an infinite recursive call and also reduce performances
 - fix in _iter_in_rendering_order method to avoid bug in edge cases (issue #107)

docs/other.rst

@@ -476,6 +476,17 @@ You can find which node is located at a given line and column:
     red.find_by_position((1, 5))
     red.find_by_position((1, 6)) # '(' is not a redbaron node
+.at()
+-------------------
+
+Returns first node at specific line
+
+.. ipython:: python
+
+    red = RedBaron("def a():\n return 42")
+    red.at(1) # Gives DefNode
+    red.at(2) # Gives ReturnNode
+
 .. _Node.from_fst:
 Node.from_fst()

redbaron/base_nodes.py

@@ -215,11 +215,13 @@ class GenericNodesUtils(object):
     def at(self, line_no):
         if line_no > self.absolute_bounding_box.bottom_right.line or \
                         line_no < self.absolute_bounding_box.top_left.line:
-            raise IndexError()
+            raise IndexError("Line number {0} is outside of the file".format(line_no))
         path = Path.from_baron_path(self, baron.path.position_to_path(self.fst(), (line_no, 1)))
         node = path.node if path else None
         if node is not None and hasattr(node, 'type') and node.type == 'endl':
-            return node.next
+            # I am not sure that it is the best solution from design point,
+            # but it is the first idea which is come to mind
+            return node.next_recursive
         return node
     def _string_to_node_list(self, string, parent, on_attribute):

tests/test_at.py

@@ -4,11 +4,11 @@
 import pytest
 import redbaron
-from redbaron import RedBaron, DecoratorNode, AssignmentNode, DefNode, EndlNode
+from redbaron import RedBaron
 redbaron.DEBUG = True
-fst = RedBaron("""\
+fst_def = RedBaron("""\
 @deco
 def foo(a, b):
@@ -17,9 +17,26 @@ def foo(a, b):
 """)
-def test_at():
-    assert isinstance(fst.at(1), DecoratorNode) is True
-    assert isinstance(fst.at(2), RedBaron) is True
-    assert isinstance(fst.at(3), DefNode) is True
-    assert isinstance(fst.at(4), AssignmentNode) is True
-    assert isinstance(fst.at(5), AssignmentNode) is True
+def test_at_def():
+    assert fst_def.at(1) is fst_def.find('DecoratorNode')
+    assert fst_def.at(2) is fst_def
+    assert fst_def.at(3) is fst_def.def_
+    assert fst_def.at(4) is fst_def.find_all('AssignmentNode')[0]
+    assert fst_def.at(5) is fst_def.find_all('AssignmentNode')[1]
+
+
+fst_class = RedBaron("""\
+class Foo(object):
+    def __init__(self):
+        self.a = None
+    def bar(self):
+        return self.a + 5
+""")
+
+
+def test_at_class():
+    assert fst_class.at(1) is fst_class.class_
+    assert fst_class.at(2) is fst_class.find_all('DefNode')[0]
+    assert fst_class.at(3) is fst_class.find('AssignmentNode')
+    assert fst_class.at(4) is fst_class.find_all('DefNode')[1]
+    assert fst_class.at(5) is fst_class.find('ReturnNode')