diff --git a/.idea/dictionaries/ericf.xml b/.idea/dictionaries/ericf.xml
index 90967037..8546cc4e 100644
--- a/.idea/dictionaries/ericf.xml
+++ b/.idea/dictionaries/ericf.xml
@@ -79,6 +79,7 @@
       <w>argval</w>
       <w>armeabi</w>
       <w>arraymodule</w>
+      <w>assertnode</w>
       <w>assetbundle</w>
       <w>assetcache</w>
       <w>assetdata</w>
@@ -196,6 +197,7 @@
       <w>calced</w>
       <w>calcing</w>
       <w>calcs</w>
+      <w>callnode</w>
       <w>cameraflash</w>
       <w>camerashake</w>
       <w>campaignname</w>
@@ -460,6 +462,7 @@
       <w>encerr</w>
       <w>endcall</w>
       <w>endindex</w>
+      <w>endparen</w>
       <w>endtime</w>
       <w>ensurepip</w>
       <w>entitylist</w>
@@ -534,6 +537,7 @@
       <w>filterpaths</w>
       <w>finalhash</w>
       <w>finalmaterials</w>
+      <w>finfo</w>
       <w>firebase</w>
       <w>firestore</w>
       <w>firetv</w>
@@ -558,6 +562,7 @@
       <w>fnum</w>
       <w>foof</w>
       <w>foos</w>
+      <w>fooval</w>
       <w>fopen</w>
       <w>forcetype</w>
       <w>forcevalue</w>
@@ -571,6 +576,7 @@
       <w>formatscriptsfull</w>
       <w>formatters</w>
       <w>fout</w>
+      <w>fparts</w>
       <w>fpath</w>
       <w>fpathrel</w>
       <w>fpathshort</w>
@@ -863,7 +869,11 @@
       <w>lindex</w>
       <w>lindexorig</w>
       <w>lineheight</w>
+      <w>lineno</w>
       <w>linenum</w>
+      <w>linenumber</w>
+      <w>linetype</w>
+      <w>linetypes</w>
       <w>linflav</w>
       <w>linkto</w>
       <w>lintable</w>
@@ -1019,6 +1029,7 @@
       <w>mypyfull</w>
       <w>mypyscripts</w>
       <w>mypyscriptsfull</w>
+      <w>mypytype</w>
       <w>mysound</w>
       <w>mytextnode</w>
       <w>myweakcall</w>
@@ -1039,6 +1050,7 @@
       <w>newdbpath</w>
       <w>newnode</w>
       <w>newpath</w>
+      <w>nextfilenum</w>
       <w>nextlevel</w>
       <w>nfoo</w>
       <w>nilly</w>
@@ -1296,6 +1308,7 @@
       <w>pypaths</w>
       <w>pysources</w>
       <w>pytest</w>
+      <w>pythondontwritebytecode</w>
       <w>pythonpath</w>
       <w>pythonw</w>
       <w>pytree</w>
@@ -1438,6 +1451,7 @@
       <w>snode</w>
       <w>socketmodule</w>
       <w>socketserver</w>
+      <w>somevar</w>
       <w>sourceimages</w>
       <w>sourcelines</w>
       <w>spacelen</w>
@@ -1483,6 +1497,8 @@
       <w>startercache</w>
       <w>startscan</w>
       <w>starttime</w>
+      <w>statictestfiles</w>
+      <w>statictype</w>
       <w>stayin</w>
       <w>stdafx</w>
       <w>stdassets</w>
@@ -1571,6 +1587,7 @@
       <w>teleporting</w>
       <w>telnetlib</w>
       <w>tempfile</w>
+      <w>tempfilepath</w>
       <w>templatecb</w>
       <w>termios</w>
       <w>testbuffer</w>
@@ -1682,6 +1699,7 @@
       <w>uname</w>
       <w>unbounds</w>
       <w>uncollectible</w>
+      <w>unforunate</w>
       <w>unimported</w>
       <w>uninferrable</w>
       <w>uninited</w>
@@ -1749,6 +1767,7 @@
       <w>vsync</w>
       <w>vsyncs</w>
       <w>vval</w>
+      <w>wanttype</w>
       <w>wasdead</w>
       <w>weakref</w>
       <w>weakrefs</w>
diff --git a/tests/test_bafoundation/test_entities.py b/tests/test_bafoundation/test_entities.py
index cf9a9f9c..487471a8 100644
--- a/tests/test_bafoundation/test_entities.py
+++ b/tests/test_bafoundation/test_entities.py
@@ -20,6 +20,15 @@
 # -----------------------------------------------------------------------------
 """Testing tests."""
 
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, List, Sequence
+
+from efrotools.statictest import static_type_equals
+
+if TYPE_CHECKING:
+    pass
+
 
 def inc(x: int) -> int:
     """Testing inc."""
@@ -28,8 +37,12 @@ def inc(x: int) -> int:
 
 def test_answer() -> None:
     """Testing answer."""
-    import bafoundation
-    print('testfooooo', dir(bafoundation))
+    fooval: List[int] = [3, 4]
+    assert static_type_equals(fooval[0], int)
+    assert static_type_equals(fooval, List[int])
+    somevar: Sequence[int] = []
+    assert static_type_equals(somevar, Sequence[int])
+    assert isinstance(fooval, list)
     assert inc(3) == 4
 
 
diff --git a/tools/efrotools/snippets.py b/tools/efrotools/snippets.py
index b5f51b07..f7faa9e8 100644
--- a/tools/efrotools/snippets.py
+++ b/tools/efrotools/snippets.py
@@ -434,7 +434,10 @@ def pytest() -> None:
     os.environ['PYTHONDONTWRITEBYTECODE'] = '1'
 
     # Do the thing.
-    subprocess.run([PYTHON_BIN, '-m', 'pytest'] + sys.argv[2:], check=True)
+    results = subprocess.run([PYTHON_BIN, '-m', 'pytest'] + sys.argv[2:],
+                             check=False)
+    if results.returncode != 0:
+        sys.exit(results.returncode)
 
 
 def makefile_target_list() -> None:
diff --git a/tools/efrotools/statictest.py b/tools/efrotools/statictest.py
new file mode 100644
index 00000000..579de664
--- /dev/null
+++ b/tools/efrotools/statictest.py
@@ -0,0 +1,191 @@
+# Copyright (c) 2011-2019 Eric Froemling
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+# -----------------------------------------------------------------------------
+"""Functionality for harnessing mypy for static type checking in unit tests."""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+import tempfile
+import os
+import subprocess
+
+if TYPE_CHECKING:
+    from typing import Any, Type, Dict, Optional, List
+
+# Global state:
+# We maintain a single temp dir where our mypy cache and our temp
+# test files live. Every time we are asked to static-check a line
+# in a file we haven't seen yet, we copy it into the temp dir,
+# filter it a bit to add reveal_type() statements, and run mypy on it.
+# The temp dir should tear itself down when Python exits.
+_tempdir: Optional[tempfile.TemporaryDirectory] = None
+_statictestfiles: Dict[str, StaticTestFile] = {}
+_nextfilenum: int = 1
+
+
+class StaticTestFile:
+    """A file which has been statically tested via mypy."""
+
+    def __init__(self, filename: str):
+        # pylint: disable=global-statement, invalid-name
+        global _tempdir, _nextfilenum
+        # pylint: enable=global-statement, invalid-name
+
+        from efrotools import PYTHON_BIN
+
+        self._filename = filename
+
+        # Types we *want* for lines
+        self.linetypes_wanted: Dict[int, str] = {}
+
+        # Types Mypy gave us for lines
+        self.linetypes_mypy: Dict[int, str] = {}
+
+        print(f"Running Mypy static testing on \"{filename}\"...")
+        with open(filename, 'r') as infile:
+            fdata = infile.read()
+
+        # Make sure we're running where the config is..
+        if not os.path.isfile('.mypy.ini'):
+            raise RuntimeError('.mypy.ini not found where expected.')
+
+        # Create a single shared temp dir
+        # (so that we can recycle our mypy cache).
+        if _tempdir is None:
+            _tempdir = tempfile.TemporaryDirectory()
+
+        # Copy our file into the temp dir with a unique name, find all
+        # instances of static_type_equals(), and run mypy type checks
+        # in those places to get static types.
+        tempfilepath = os.path.join(_tempdir.name, f'temp{_nextfilenum}.py')
+        _nextfilenum += 1
+        with open(tempfilepath, 'w') as outfile:
+            outfile.write(self.filter_file_contents(fdata))
+        results = subprocess.run([
+            PYTHON_BIN, '-m', 'mypy', '--no-error-summary', '--config-file',
+            '.mypy.ini', '--cache-dir', _tempdir.name, tempfilepath
+        ],
+                                 capture_output=True,
+                                 check=False)
+        # HMM; it seems we get an errored return code due to reveal_type()s.
+        # So I guess we just have to ignore other errors, which is unforunate.
+        # (though if the run fails, we'll probably error when attempting to
+        # look up a revealed type that we don't have anyway)
+        lines = results.stdout.decode().splitlines()
+        for line in lines:
+            if 'Revealed type is ' in line:
+                finfo = line.split(' ')[0]
+                fparts = finfo.split(':')
+                assert len(fparts) == 3
+                linenumber = int(fparts[1])
+                linetype = line.split('Revealed type is ')[-1][1:-1]
+                self.linetypes_mypy[linenumber] = linetype
+
+    def filter_file_contents(self, contents: str) -> str:
+        """Filter the provided file contents and take note of type checks."""
+        import ast
+        lines = contents.splitlines()
+        lines_out: List[str] = []
+        for lineno, line in enumerate(lines):
+            if 'static_type_equals(' not in line:
+                lines_out.append(line)
+            else:
+
+                # Find the location of the end parentheses.
+                assert ')' in line
+                endparen = len(line) - 1
+                while line[endparen] != ')':
+                    endparen -= 1
+
+                # Find the offset to the start of the line.
+                offset = 0
+                while line[offset] == ' ':
+                    offset += 1
+
+                # Parse this line as AST - we should find an assert
+                # statement containing a static_type_equals() call
+                # with 2 args.
+                tree = ast.parse(line[offset:])
+                assert isinstance(tree, ast.Module)
+                if (len(tree.body) != 1
+                        or not isinstance(tree.body[0], ast.Assert)):
+                    raise RuntimeError(
+                        f"{self._filename} line {lineno+1}: expected "
+                        f" a single assert statement.")
+                assertnode = tree.body[0]
+                callnode = assertnode.test
+                if (not isinstance(callnode, ast.Call)
+                        or not isinstance(callnode.func, ast.Name)
+                        or callnode.func.id != 'static_type_equals'
+                        or len(callnode.args) != 2):
+                    raise RuntimeError(
+                        f"{self._filename} line {lineno+1}: expected "
+                        f" a single static_type_equals() call with 2 args.")
+
+                # Use the column offsets for the 2 args along with our end
+                # paren offset to cut out the substrings representing the args.
+                arg1 = line[callnode.args[0].col_offset +
+                            offset:callnode.args[1].col_offset + offset]
+                while arg1[-1] in (' ', ','):
+                    arg1 = arg1[:-1]
+                arg2 = line[callnode.args[1].col_offset + offset:endparen]
+
+                # In our filtered file, replace the assert statement with
+                # a reveal_type() for the var, and also take note of the
+                # type they want it to equal.
+                self.linetypes_wanted[lineno + 1] = arg2
+                lines_out.append(' ' * offset + f'reveal_type({arg1})')
+
+        return '\n'.join(lines_out) + '\n'
+
+
+def static_type_equals(value: Any, statictype: Type) -> bool:
+    """Check a type statically using mypy."""
+    from inspect import getframeinfo, stack
+
+    # We don't actually use there here; we pull them as strings from the src.
+    del value
+    del statictype
+
+    # Get the filename and line number of the calling function.
+    caller = getframeinfo(stack()[1][0])
+    filename = caller.filename
+    linenumber = caller.lineno
+
+    if filename not in _statictestfiles:
+        _statictestfiles[filename] = StaticTestFile(filename)
+
+    wanttype = _statictestfiles[filename].linetypes_wanted[linenumber]
+    mypytype = _statictestfiles[filename].linetypes_mypy[linenumber]
+
+    # Do some filtering of Mypy types to simple python ones.
+    # (ie: 'builtins.list[builtins.int*]' -> int)
+    mypytype = mypytype.replace('builtins.int*', 'int')
+    mypytype = mypytype.replace('builtins.int', 'int')
+    mypytype = mypytype.replace('builtins.list', 'List')
+    mypytype = mypytype.replace('typing.Sequence', 'Sequence')
+
+    if wanttype != mypytype:
+        print(f'Mypy type "{mypytype}" does not match '
+              f'the desired type "{wanttype}" on line {linenumber}.')
+        return False
+
+    return True