android: Add build `py-funcsigs` and unit tests

Needed as a dependency for pytest.

Bug: 112283442
diff --git a/Android.bp b/Android.bp
new file mode 100644
index 0000000..c4787f0
--- /dev/null
+++ b/Android.bp
@@ -0,0 +1,59 @@
+// Copyright 2018 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+python_test {
+  name: "py2-funcsigs-tests",
+  // use _ instead of . in the name to avoid error:
+  //   error: external/python/funcsigs/Android.bp:18:7: module "py2-funcsigs-tests" variant
+  //   "linux_glibc_x86_64_PY2": srcs: the path "Android.tests.py" contains invalid token "Android.tests".
+  main: "Android_tests.py",
+  srcs: [
+      // important: the tests must be run as if they were in the 'tests' module
+      // (i.e. from external/python/funcsigs) otherwise one of the tests will fail.
+      "tests/*.py",
+      "Android_tests.py",
+  ],
+  host_supported: true,
+  libs: ["py-funcsigs"],
+  version: {
+    py2: {
+      enabled: true,
+    },
+    py3: {
+      enabled: false,
+    },
+  },
+  // required for tests.test_funcsigs.TestFunctionSignatures
+  data: ["README.rst"],
+}
+
+python_test {
+  name: "py3-funcsigs-tests",
+  main: "Android_tests.py",
+  srcs: [
+      "tests/*.py",
+      "Android_tests.py",
+  ],
+  host_supported: true,
+  libs: ["py-funcsigs"],
+  version: {
+    py2: {
+      enabled: false,
+    },
+    py3: {
+      enabled: true,
+    },
+  },
+  data: ["README.rst"],
+}
diff --git a/Android_tests.py b/Android_tests.py
new file mode 100644
index 0000000..ac84729
--- /dev/null
+++ b/Android_tests.py
@@ -0,0 +1,33 @@
+# Copyright 2018 Google Inc. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+import sys
+import unittest
+
+# this runs any test*.py files located anywhere in this subtree
+if __name__ == '__main__':
+  test_loader = unittest.defaultTestLoader
+  # output is normal text formatting (as if running from a CLI), prints to stderr
+  test_runner = unittest.TextTestRunner(stream=sys.stderr)
+
+  # look at tests relative to the dir of this file.
+  this_dir = os.path.dirname(os.path.abspath(__file__))
+
+  # automagically find all tests recursively whose file name matches test*.py
+  test_suite = test_loader.discover(this_dir, pattern='test*.py')
+
+  # execute all the found tests
+  test_runner.run(test_suite)
+
diff --git a/funcsigs/Android.bp b/funcsigs/Android.bp
new file mode 100644
index 0000000..acee033
--- /dev/null
+++ b/funcsigs/Android.bp
@@ -0,0 +1,30 @@
+// Copyright 2018 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+python_library {
+  name: "py-funcsigs",
+  host_supported: true,
+  srcs: [
+      "*.py",
+  ],
+  version: {
+        py2: {
+            enabled: true,
+        },
+        py3: {
+            enabled: true,
+        },
+  },
+  pkg_path: "funcsigs",
+}