Added built-in len function

pyState/functions/len.py

@@ -0,0 +1,19 @@
+from pyObjectManager.Int import Int
+
+def handle(state,call,obj):
+    """
+    Simulate len funcion
+    """
+    # Resolve the object
+    obj = state.resolveObject(obj)
+
+    # Just calling the length function on the object..
+    l = obj.length()
+
+    i = state.getVar("tmpLenValue",ctx=1, varType=Int)
+    i.increment()
+
+    # Tell Z3 about our value
+    state.addConstraint(i.getZ3Object() == l)
+
+    return i.copy()

tests/test_function_len.py

@@ -0,0 +1,37 @@
+import sys, os
+myPath = os.path.dirname(os.path.abspath(__file__))
+sys.path.insert(0, myPath + '/../')
+
+import logging
+import Colorer
+logging.basicConfig(level=logging.DEBUG,format='%(name)s - %(levelname)s - %(message)s', datefmt='%m/%d/%Y %I:%M:%S %p')
+
+import ast
+import z3
+from pyPath import Path
+from pyPathGroup import PathGroup
+import pytest
+from pyObjectManager.Int import Int
+from pyObjectManager.Real import Real
+from pyObjectManager.BitVec import BitVec
+from pyObjectManager.List import List
+
+test1 = """
+s = "abcd"
+l = [x for x in s] + [1,2]
+x = len(s)
+y = len(l)
+"""
+
+
+def test_function_len():
+    b = ast.parse(test1).body
+    p = Path(b,source=test1)
+    pg = PathGroup(p)
+
+    pg.explore()
+    assert len(pg.completed) == 1
+
+    assert pg.completed[0].state.any_int('x') == 4
+    assert pg.completed[0].state.any_int('y') == 6
+