split node tests into standalone files

tests/node_tests/test_coordinate.py

@@ -0,0 +1,14 @@
+def test_coordinate():
+    from backend.nodes.coordinate import Coordinate
+
+    node = Coordinate()
+
+    result = node.process(x=0.3, y=0.7)
+    assert len(result) == 1
+    assert result[0] == (0.3, 0.7)
+
+    result_zero = node.process(x=0.0, y=0.0)
+    assert result_zero[0] == (0.0, 0.0)
+
+    result_one = node.process(x=1.0, y=1.0)
+    assert result_one[0] == (1.0, 1.0)