Start adding tests for new pipeline management

spacy/tests/pipeline/test_add_pipe.py

@@ -0,0 +1,43 @@
+from __future__ import unicode_literals
+import pytest
+
+from ... import language
+from ...language import Language
+
+@pytest.fixture
+def nlp():
+    return Language()
+
+@pytest.fixture
+def name():
+    return 'parser'
+
+def new_pipe(doc):
+    return doc
+
+
+def test_add_pipe_no_name(nlp):
+    nlp.add_pipe(new_pipe)
+    assert 'new_pipe' in nlp.pipe_names
+
+def test_add_pipe_duplicate_name(nlp):
+    nlp.add_pipe(new_pipe, name='duplicate_name')
+    with pytest.raises(ValueError):
+        nlp.add_pipe(new_pipe, name='duplicate_name')
+
+
+def test_add_pipe_first(nlp, name):
+    nlp.add_pipe(new_pipe, name=name, first=True)
+    assert nlp.pipeline[0][0] == name
+
+
+def test_add_pipe_last(nlp, name):
+    nlp.add_pipe(lambda doc: doc, name='lambda_pipe')
+    nlp.add_pipe(new_pipe, name=name, last=True)
+    assert nlp.pipeline[0][0] != name
+    assert nlp.pipeline[-1][0] == name
+
+
+def test_cant_add_pipe_first_and_last(nlp):
+    with pytest.raises(ValueError):
+        nlp.add_pipe(new_pipe, first=True, last=True)