added test_cells_with_symbol() : find source lines with symbol in a g…

…iven file name

test_nbutils.py

@@ -38,6 +38,18 @@ def test_has_symbol(self):
 
         self.assertSequenceEqual(expected, result)
 
+    def test_cells_with_symbol(self):
+        result = nbutils.symbol_lines_in_file(self.input_file_name)
+
+        # compare with an expected list
+        expected = [(8, [(0, "L_AB_m = sy.symbols('L_AB_m', real=True, nonnegative=True)")]),
+                    (10, [(0, "w0_N_m = sy.symbols('w0_N_m', real=True)")]),
+                    (12, [(0, "E_Pa, I_m4 = sy.symbols('E_Pa, I_m4', positive=True)")]),
+                    (14, [(0, "x_m = sy.symbols('x_m', nonnegative=True)")]),
+                    (16, [(0, "R_A_N, M_A_Nm, R_B_N = sy.symbols('R_A_N, M_A_Nm, R_B_N', real=True)")])]
+
+        self.assertSequenceEqual(expected, result)
+
     def test_replace_symbol(self):
         file = nbutils.read_file(self.input_file_name)
         cells = file['cells']