Added test cases for ast nodes

pystencils_tests/test_astnodes.py

+import sympy as sp
+import pystencils as ps
+
+from pystencils import Assignment
+from pystencils.astnodes import Block, SkipIteration, LoopOverCoordinate, SympyAssignment
+from sympy.codegen.rewriting import optims_c99
+
+dst = ps.fields('dst(8): double[2D]')
+s = sp.symbols('s_:8')
+x = sp.symbols('x')
+y = sp.symbols('y')
+
+
+def test_kernel_function():
+    assignments = [
+        Assignment(dst[0, 0](0), s[0]),
+        Assignment(x, dst[0, 0](2))
+    ]
+
+    ast_node = ps.create_kernel(assignments)
+
+    assert ast_node.target == 'cpu'
+    assert ast_node.backend == 'c'
+    # symbols_defined and undefined_symbols will always return an emtpy set
+    assert ast_node.symbols_defined == set()
+    assert ast_node.undefined_symbols == set()
+    assert ast_node.fields_written == {dst}
+    assert ast_node.fields_read == {dst}
+
+
+def test_skip_iteration():
+    # skip iteration is an object which should give back empty data structures.
+    skipped = SkipIteration()
+    assert skipped.args == []
+    assert skipped.symbols_defined == set()
+    assert skipped.undefined_symbols == set()
+
+
+def test_block():
+    assignments = [
+        Assignment(dst[0, 0](0), s[0]),
+        Assignment(x, dst[0, 0](2))
+    ]
+    bl = Block(assignments)
+    assert bl.symbols_defined == {dst[0, 0](0), dst[0, 0](2), s[0], x}
+
+    bl.append([Assignment(y, 10)])
+    assert bl.symbols_defined == {dst[0, 0](0), dst[0, 0](2), s[0], x, y}
+    assert len(bl.args) == 3
+
+    list_iterator = iter([Assignment(s[1], 11)])
+    bl.insert_front(list_iterator)
+
+    assert bl.args[0] == Assignment(s[1], 11)
+
+
+def test_loop_over_coordinate():
+    assignments = [
+        Assignment(dst[0, 0](0), s[0]),
+        Assignment(x, dst[0, 0](2))
+    ]
+
+    body = Block(assignments)
+    loop = LoopOverCoordinate(body, coordinate_to_loop_over=0, start=0, stop=10, step=1)
+
+    assert loop.body == body
+
+    new_body = Block([assignments[0]])
+    loop = loop.new_loop_with_different_body(new_body)
+    assert loop.body == new_body
+
+    assert loop.start == 0
+    assert loop.stop == 10
+    assert loop.step == 1
+
+    loop.replace(loop.start, 2)
+    loop.replace(loop.stop, 20)
+    loop.replace(loop.step, 2)
+
+    assert loop.start == 2
+    assert loop.stop == 20
+    assert loop.step == 2
+
+
+def test_sympy_assignment():
+
+    assignment = SympyAssignment(dst[0, 0](0), sp.log(x + 3) / sp.log(2) + sp.log(x ** 2 + 1))
+    assignment.optimize(optims_c99)
+
+    ast = ps.create_kernel([assignment])
+    code = ps.get_code_str(ast)
+
+    assert 'log1p' in code
+    assert 'log2' in code
+
+    assignment.replace(assignment.lhs, dst[0, 0](1))
+    assignment.replace(assignment.rhs, sp.log(2))
+
+    assert assignment.lhs == dst[0, 0](1)
+    assert assignment.rhs == sp.log(2)