Add the Script.help function, fixes #392

test/test_api/test_documentation.py

@@ -0,0 +1,52 @@
+import pytest
+
+
+def test_error_leaf_keyword_doc(Script):
+    d, = Script("or").help(1, 1)
+    assert len(d.docstring()) > 100
+    assert d.name == 'or'
+
+
+def test_error_leaf_operator_doc(Script):
+    d, = Script("==").help()
+    assert len(d.docstring()) > 100
+    assert d.name == '=='
+
+
+def test_keyword_completion(Script):
+    k = Script("fro").complete()[0]
+    imp_start = 'The "import'
+    assert k.docstring(raw=True).startswith(imp_start)
+    assert k.docstring().startswith(imp_start)
+
+
+def test_import_keyword(Script):
+    d, = Script("import x").help(column=0)
+    assert d.docstring().startswith('The "import" statement')
+    # unrelated to #44
+
+
+def test_import_keyword_with_gotos(goto_or_infer):
+    assert not goto_or_infer("import x", column=0)
+
+
+def test_operator_doc(Script):
+    d, = Script("a == b").help(1, 3)
+    assert len(d.docstring()) > 100
+
+
+def test_lambda(Script):
+    d, = Script('lambda x: x').help(column=0)
+    assert d.type == 'keyword'
+    assert d.docstring().startswith('Lambdas\n*******')
+
+
+@pytest.mark.parametrize(
+    'code, kwargs', [
+        ('?', {}),
+        ('""', {}),
+        ('"', {}),
+    ]
+)
+def test_help_no_returns(Script, code, kwargs):
+    assert not Script(code).help(**kwargs)