New syntax: adding test cases and syntactic sugar tools in graph api for merges and forks (related to #323 and #324, allows #328).

tests/structs/test_graphs_new_syntax.py

@@ -0,0 +1,129 @@
+from operator import attrgetter
+from unittest.mock import sentinel
+
+import pytest
+
+from bonobo.constants import BEGIN
+from bonobo.structs.graphs import Graph, GraphCursor
+from bonobo.util import tuplize
+
+
+@tuplize
+def get_pseudo_nodes(*names):
+    for name in names:
+        yield getattr(sentinel, name)
+
+
+def test_get_cursor():
+    g = Graph()
+    cursor = g.get_cursor()
+
+    assert cursor.graph is g
+    assert cursor.first is BEGIN
+    assert cursor.last is BEGIN
+
+
+def test_get_cursor_in_a_vacuum():
+    g = Graph()
+    cursor = g.get_cursor(None)
+
+    assert cursor.graph is g
+    assert cursor.first is None
+    assert cursor.last is None
+
+
+def test_cursor_usage_to_add_a_chain():
+    a, b, c = get_pseudo_nodes(*"abc")
+
+    g = Graph()
+
+    g.get_cursor() >> a >> b >> c
+
+    assert len(g) == 3
+    assert g.outputs_of(BEGIN) == {g.index_of(a)}
+    assert g.outputs_of(a) == {g.index_of(b)}
+    assert g.outputs_of(b) == {g.index_of(c)}
+    assert g.outputs_of(c) == set()
+
+
+def test_cursor_usage_to_add_a_chain_in_a_context_manager():
+    a, b, c = get_pseudo_nodes(*"abc")
+
+    g = Graph()
+    with g as cur:
+        cur >> a >> b >> c
+
+    assert len(g) == 3
+    assert g.outputs_of(BEGIN) == {g.index_of(a)}
+    assert g.outputs_of(a) == {g.index_of(b)}
+    assert g.outputs_of(b) == {g.index_of(c)}
+    assert g.outputs_of(c) == set()
+
+
+def test_implicit_cursor_usage():
+    a, b, c = get_pseudo_nodes(*"abc")
+
+    g = Graph()
+    g >> a >> b >> c
+
+    assert len(g) == 3
+    assert g.outputs_of(BEGIN) == {g.index_of(a)}
+    assert g.outputs_of(a) == {g.index_of(b)}
+    assert g.outputs_of(b) == {g.index_of(c)}
+    assert g.outputs_of(c) == set()
+
+
+def test_cursor_to_fork_a_graph():
+    a, b, c, d, e = get_pseudo_nodes(*"abcde")
+
+    g = Graph()
+    g >> a >> b >> c
+    g.get_cursor(b) >> d >> e
+
+    assert len(g) == 5
+    assert g.outputs_of(BEGIN) == {g.index_of(a)}
+    assert g.outputs_of(a) == {g.index_of(b)}
+    assert g.outputs_of(b) == {g.index_of(c), g.index_of(d)}
+    assert g.outputs_of(c) == set()
+    assert g.outputs_of(d) == {g.index_of(e)}
+    assert g.outputs_of(e) == set()
+
+
+def test_cursor_to_fork_at_the_end():
+    a, b, c, d, e = get_pseudo_nodes(*"abcde")
+
+    g = Graph()
+    c0 = g >> a >> b
+    c1 = c0 >> c
+    c2 = c0 >> d >> e
+
+    assert len(g) == 5
+    assert g.outputs_of(BEGIN) == {g.index_of(a)}
+    assert g.outputs_of(a) == {g.index_of(b)}
+    assert g.outputs_of(b) == {g.index_of(c), g.index_of(d)}
+    assert g.outputs_of(c) == set()
+    assert g.outputs_of(d) == {g.index_of(e)}
+    assert g.outputs_of(e) == set()
+
+    assert c0.first == g.index_of(BEGIN)
+    assert c0.last == g.index_of(b)
+    assert c1.first == g.index_of(BEGIN)
+    assert c1.last == g.index_of(c)
+    assert c2.first == g.index_of(BEGIN)
+    assert c2.last == g.index_of(e)
+
+
+def test_cursor_merge():
+    a, b, c = get_pseudo_nodes(*"abc")
+    g = Graph()
+
+    c1 = g >> a >> c
+    c2 = g >> b >> c
+
+    assert len(g) == 3
+    assert g.outputs_of(BEGIN) == g.indexes_of(a, b)
+    assert g.outputs_of(a) == g.indexes_of(c)
+    assert g.outputs_of(b) == g.indexes_of(c)
+    assert g.outputs_of(c) == set()
+
+    assert c1 == c2