Test function refactor (#273)

Summary:
Pull Request resolved: #273

Moves the test function refactor into OSS and consolidates the augmented funtions for multi-fidelity optimization.

Still needs some cleaning up, full test coverage, and some work on docstrings.

I considered making this change in a backward-compatible fashion, but I don't think it's worth the work and the code bloat.

Reviewed By: danielrjiang

Differential Revision: D17501790

fbshipit-source-id: b6cfac9ae27089da6b73c93f161f3ed9ff12785e

Author: Balandat

botorch/test_functions/__init__.py

@@ -2,25 +2,55 @@
 
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
 
-from .aug_branin import neg_aug_branin
-from .aug_hartmann6 import neg_aug_hartmann6
-from .aug_rosenbrock import neg_aug_rosenbrock
-from .branin import neg_branin
-from .eggholder import neg_eggholder
-from .hartmann6 import neg_hartmann6
-from .holder_table import neg_holder_table
-from .michalewicz import neg_michalewicz
-from .styblinski_tang import neg_styblinski_tang
+from .multi_fidelity import AugmentedBranin, AugmentedHartmann, AugmentedRosenbrock
+from .synthetic import (
+    Ackley,
+    Beale,
+    Branin,
+    Bukin,
+    Cosine8,
+    DixonPrice,
+    DropWave,
+    EggHolder,
+    Griewank,
+    Hartmann,
+    HolderTable,
+    Levy,
+    Michalewicz,
+    Powell,
+    Rastrigin,
+    Rosenbrock,
+    Shekel,
+    SixHumpCamel,
+    StyblinskiTang,
+    SyntheticTestFunction,
+    ThreeHumpCamel,
+)
 
 
 __all__ = [
-    "neg_branin",
-    "neg_eggholder",
-    "neg_hartmann6",
-    "neg_holder_table",
-    "neg_michalewicz",
-    "neg_styblinski_tang",
-    "neg_aug_branin",
-    "neg_aug_hartmann6",
-    "neg_aug_rosenbrock",
+    "Ackley",
+    "AugmentedBranin",
+    "AugmentedHartmann",
+    "AugmentedRosenbrock",
+    "Beale",
+    "Branin",
+    "Bukin",
+    "Cosine8",
+    "DixonPrice",
+    "DropWave",
+    "EggHolder",
+    "Griewank",
+    "Hartmann",
+    "HolderTable",
+    "Levy",
+    "Michalewicz",
+    "Powell",
+    "Rastrigin",
+    "Rosenbrock",
+    "Shekel",
+    "SixHumpCamel",
+    "StyblinskiTang",
+    "SyntheticTestFunction",
+    "ThreeHumpCamel",
 ]