WIP: Allow use of symbolic function in equation and add test

essm/variables/_core.py

@@ -232,10 +232,10 @@ def collect_factor_and_basedimension(expr):
         elif isinstance(expr, Function):
             fds = {Variable.collect_factor_and_basedimension(
                 arg)[1] for arg in expr.args}
-            if fds != {Dimension(1)}:
-                raise ValueError(
-                    'Arguments in function are not dimensionless, '
-                    'but have dimensions of {0}'.format(fds))
+            # if fds != {Dimension(1)}:
+            #     raise ValueError(
+            #         'Arguments in function are not dimensionless, '
+            #         'but have dimensions of {0}'.format(fds))
             return expr, Dimension(1)
         elif isinstance(expr, Dimension):
             return 1, expr

tests/test_equations.py

@@ -11,7 +11,7 @@
                                   derive_baseunit)
 from essm.variables.utils import (extract_variables, replace_defaults,
                                   replace_variables)
-from sympy import cos, Derivative, exp, log, S, Symbol, solve, sqrt
+from sympy import cos, Derivative, exp, Function, log, S, Symbol, solve, sqrt
 from sympy.physics.units import Quantity, length, meter
 
 
@@ -288,6 +288,15 @@ class var_joule_base(Variable):
         1 - exp(var_joule/var_joule_base)
 
 
+def test_check_unit_function():
+    """
+    Make sure that check_unit works with symbolic functions"""
+
+    f = Function('f')(demo_t)
+    assert Variable.check_unit(Derivative(f, demo_t)) == \
+        Derivative(f, demo_t)
+
+
 def test_double_registration():
     """Check double registration warning."""