diff --git a/tools/build_rules/prelude_bazel b/tools/build_rules/prelude_bazel
index c6037e7..4d8b204 100644
--- a/tools/build_rules/prelude_bazel
+++ b/tools/build_rules/prelude_bazel
@@ -6,6 +6,7 @@ load("//tools/python:defs.bzl",
      "py_unittest",
      "py_pytest",
      "py_resources",
+     "py_project",
 )
 
 load("@arrdem_source_pypi//:requirements.bzl",
diff --git a/tools/python/defs.bzl b/tools/python/defs.bzl
index 6239f23..929daf8 100644
--- a/tools/python/defs.bzl
+++ b/tools/python/defs.bzl
@@ -10,102 +10,102 @@ load("@rules_python//python:defs.bzl",
 
 
 def py_requirement(*args, **kwargs):
-  """A re-export of requirement()"""
-  return _py_requirement(*args, **kwargs)
+    """A re-export of requirement()"""
+    return _py_requirement(*args, **kwargs)
 
 
 def py_test(python_version=None, **kwargs):
-  """A re-export of py_test()"""
+    """A re-export of py_test()"""
 
-  if python_version and python_version != "PY3":
-    fail("py3k only!")
+    if python_version and python_version != "PY3":
+        fail("py3k only!")
 
-  return _py_test(
-    python_version="PY3",
-    **kwargs,
-  )
+    return _py_test(
+        python_version="PY3",
+        **kwargs,
+    )
 
 
 def py_pytest(name, srcs, deps, main=None, python_version=None, args=None, **kwargs):
-  """A py_test target which uses pytest."""
+    """A py_test target which uses pytest."""
 
-  if python_version and python_version != "PY3":
-    fail("py3k only!")
+    if python_version and python_version != "PY3":
+        fail("py3k only!")
 
-  f = "//tools/python:bzl_pytest_shim.py"
+    f = "//tools/python:bzl_pytest_shim.py"
 
-  deps = [
-      py_requirement("pytest"),
-      py_requirement("jedi"),
-      py_requirement("pytest-pudb"),
-  ] + deps
+    deps = [
+        py_requirement("pytest"),
+        py_requirement("jedi"),
+        py_requirement("pytest-pudb"),
+    ] + deps
 
-  srcs = [f] + srcs
+    srcs = [f] + srcs
 
-  t = py_test(
-    name = name,
-    srcs = srcs,
-    main = f,
-    args = args,
-    python_version="PY3",
-    deps = deps,
-    **kwargs,
-  )
+    t = py_test(
+      name = name,
+      srcs = srcs,
+      main = f,
+      args = args,
+      python_version="PY3",
+      deps = deps,
+      **kwargs,
+    )
 
-  # FIXME (arrdem 2020-09-27):
-  #   This really needs to be a py_image_test.
-  #   Not clear how to achieve that.
-  # py_image(
-  #   name = name + ".containerized",
-  #   main = f,
-  #   args = args,
-  #   srcs = srcs,
-  #   deps = deps,
-  #   **kwargs,
-  # )
+    # FIXME (arrdem 2020-09-27):
+    #   This really needs to be a py_image_test.
+    #   Not clear how to achieve that.
+    # py_image(
+    #   name = name + ".containerized",
+    #   main = f,
+    #   args = args,
+    #   srcs = srcs,
+    #   deps = deps,
+    #   **kwargs,
+    # )
 
-  return t
+    return t
 
 
 def py_unittest(srcs=[], **kwargs):
-  """A helper for running unittest tests"""
+    """A helper for running unittest tests"""
 
-  f = "//tools/python:bzl_unittest_shim.py"
-  return py_test(
-      main = f,
-      srcs = [f] + srcs,
-      **kwargs
-  )
+    f = "//tools/python:bzl_unittest_shim.py"
+    return py_test(
+        main = f,
+        srcs = [f] + srcs,
+        **kwargs
+    )
 
 
 def py_binary(python_version=None, main=None, srcs=None, **kwargs):
-  """A re-export of py_binary()"""
+    """A re-export of py_binary()"""
 
-  if python_version and python_version != "PY3":
-    fail("py3k only!")
+    if python_version and python_version != "PY3":
+        fail("py3k only!")
 
-  srcs = srcs or []
-  if main not in srcs:
-    srcs = [main] + srcs
+    srcs = srcs or []
+    if main not in srcs:
+        srcs = [main] + srcs
 
-  return _py_binary(
-    python_version = "PY3",
-    main = main,
-    srcs = srcs,
-    **kwargs,
-  )
+    return _py_binary(
+        python_version = "PY3",
+        main = main,
+        srcs = srcs,
+        **kwargs,
+    )
 
 
 def py_library(srcs_version=None, **kwargs):
-  """A re-export of py_library()"""
+    """A re-export of py_library()"""
 
-  if srcs_version and srcs_version != "PY3":
-    fail("py3k only!")
+    if srcs_version and srcs_version != "PY3":
+        fail("py3k only!")
 
-  return _py_library(
-    srcs_version="PY3",
-    **kwargs
-  )
+    return _py_library(
+        srcs_version="PY3",
+        **kwargs
+    )
 
 
 ResourceGroupInfo = provider(
@@ -144,3 +144,37 @@ py_resources = rule(
         ),
     },
 )
+
+def py_project(name=None,
+               lib_srcs=None,
+               lib_deps=None,
+               test_srcs=None,
+               test_deps=None):
+    """
+    A helper for defining conventionally-formatted python project.
+
+    Assumes that there's a src/python tree, and a src/test tree.
+
+    Each test_*.py source generates its own implicit test target. This allows
+    for automatic test parallelism.
+
+    """
+
+    lib_srcs = lib_srcs or native.glob(["src/python/**/*.py"])
+    test_srcs = test_srcs or native.glob(["test/python/**/*.py"])
+
+    py_library(
+        name=name,
+        srcs=lib_srcs,
+        deps=lib_deps,
+        imports=["src/python"],
+    )
+
+    for src in test_srcs:
+        if "test_" in src:
+            py_pytest(
+                name=name + ".test." + str(hash(src)).replace("-", "") + "." + src.split("/")[-1],
+                srcs=test_srcs,
+                deps=[name] + test_deps,
+                imports=["test/python"],
+            )