Add a SQL agent for interacting with SQL Databases and JSON Agent for interacting with large JSON blobs (#1150)

This PR adds 

* `ZeroShotAgent.as_sql_agent`, which returns an agent for interacting
with a sql database. This builds off of `SQLDatabaseChain`. The main
advantages are 1) answering general questions about the db, 2) access to
a tool for double checking queries, and 3) recovering from errors
* `ZeroShotAgent.as_json_agent` which returns an agent for interacting
with json blobs.
* Several examples in notebooks

---------

Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>

tests/unit_tests/chains/test_api.py

@@ -16,7 +16,7 @@ class FakeRequestsChain(RequestsWrapper):
 
     output: str
 
-    def run(self, url: str) -> str:
+    def get(self, url: str) -> str:
         """Just return the specified output."""
         return self.output
 

tests/unit_tests/test_python.py

@@ -9,11 +9,13 @@ def test_python_repl() -> None:
 
     # Run a simple initial command.
     repl.run("foo = 1")
-    assert repl._locals["foo"] == 1
+    assert repl.locals is not None
+    assert repl.locals["foo"] == 1
 
     # Now run a command that accesses `foo` to make sure it still has it.
     repl.run("bar = foo * 2")
-    assert repl._locals["bar"] == 2
+    assert repl.locals is not None
+    assert repl.locals["bar"] == 2
 
 
 def test_python_repl_no_previous_variables() -> None:
@@ -29,7 +31,8 @@ def test_python_repl_pass_in_locals() -> None:
     _locals = {"foo": 4}
     repl = PythonREPL(_locals=_locals)
     repl.run("bar = foo * 2")
-    assert repl._locals["bar"] == 8
+    assert repl.locals is not None
+    assert repl.locals["bar"] == 8
 
 
 def test_functionality() -> None:
@@ -38,3 +41,15 @@ def test_functionality() -> None:
     code = "print(1 + 1)"
     output = chain.run(code)
     assert output == "2\n"
+
+
+def test_function() -> None:
+    """Test correct functionality."""
+    chain = PythonREPL()
+    code = "def add(a, b): " "    return a + b"
+    output = chain.run(code)
+    assert output == ""
+
+    code = "print(add(1, 2))"
+    output = chain.run(code)
+    assert output == "3\n"

tests/unit_tests/tools/__init__.py

@@ -0,0 +1 @@
+"""Test suite for the tools module."""

tests/unit_tests/tools/test_json.py

@@ -0,0 +1,49 @@
+"""Test functionality of JSON tools."""
+from pathlib import Path
+
+from langchain.tools.json.tool import JsonSpec
+
+
+def test_json_spec_from_file(tmp_path: Path) -> None:
+    """Test JsonSpec can be constructed from a file."""
+    path = tmp_path / "test.json"
+    path.write_text('{"foo": "bar"}')
+    spec = JsonSpec.from_file(path)
+    assert spec.dict_ == {"foo": "bar"}
+
+
+def test_json_spec_keys() -> None:
+    """Test JsonSpec can return keys of a dict at given path."""
+    spec = JsonSpec(dict_={"foo": "bar", "baz": {"test": {"foo": [1, 2, 3]}}})
+    assert spec.keys("data") == "['foo', 'baz']"
+    assert "ValueError" in spec.keys('data["foo"]')
+    assert spec.keys('data["baz"]') == "['test']"
+    assert spec.keys('data["baz"]["test"]') == "['foo']"
+    assert "ValueError" in spec.keys('data["baz"]["test"]["foo"]')
+
+
+def test_json_spec_value() -> None:
+    """Test JsonSpec can return value of a dict at given path."""
+    spec = JsonSpec(dict_={"foo": "bar", "baz": {"test": {"foo": [1, 2, 3]}}})
+    assert spec.value("data") == "{'foo': 'bar', 'baz': {'test': {'foo': [1, 2, 3]}}}"
+    assert spec.value('data["foo"]') == "bar"
+    assert spec.value('data["baz"]') == "{'test': {'foo': [1, 2, 3]}}"
+    assert spec.value('data["baz"]["test"]') == "{'foo': [1, 2, 3]}"
+    assert spec.value('data["baz"]["test"]["foo"]') == "[1, 2, 3]"
+
+
+def test_json_spec_value_max_length() -> None:
+    """Test JsonSpec can return value of a dict at given path."""
+    spec = JsonSpec(
+        dict_={"foo": "bar", "baz": {"test": {"foo": [1, 2, 3]}}}, max_value_length=5
+    )
+    assert spec.value('data["foo"]') == "bar"
+    assert (
+        spec.value('data["baz"]')
+        == "Value is a large dictionary, should explore its keys directly"
+    )
+    assert (
+        spec.value('data["baz"]["test"]')
+        == "Value is a large dictionary, should explore its keys directly"
+    )
+    assert spec.value('data["baz"]["test"]["foo"]') == "[1, 2..."