diff --git a/eden/fs/cli/test/config_test.py b/eden/fs/cli/test/config_test.py
index dff787249c..367fbe3aca 100644
--- a/eden/fs/cli/test/config_test.py
+++ b/eden/fs/cli/test/config_test.py
@@ -4,6 +4,8 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2.
 
+# pyre-strict
+
 import configparser
 import io
 import os
@@ -22,14 +24,14 @@ from ..configinterpolator import EdenConfigInterpolator
 from ..configutil import EdenConfigParser, UnexpectedType
 
 
-def get_toml_test_file_invalid():
+def get_toml_test_file_invalid() -> str:
     cfg_file = """
 [core thisIsNotAllowed]
 """
     return cfg_file
 
 
-def get_toml_test_file_defaults():
+def get_toml_test_file_defaults() -> str:
     cfg_file = """
 [core]
 systemIgnoreFile = "/etc/eden/gitignore"
@@ -44,7 +46,7 @@ reporter = 'pastry --title "eden rage from $(hostname)"'
     return cfg_file
 
 
-def get_toml_test_file_user_rc():
+def get_toml_test_file_user_rc() -> str:
     cfg_file = """
 [core]
 ignoreFile = "/home/${USER}/.gitignore-override"
@@ -56,7 +58,7 @@ scribe-cat = "/usr/local/bin/scribe_cat"
     return cfg_file
 
 
-def get_toml_test_file_system_rc():
+def get_toml_test_file_system_rc() -> str:
     cfg_file = """
 ["telemetry"]
 scribe-cat = "/bad/path/to/scribe_cat"
diff --git a/eden/fs/cli/test/debug_test.py b/eden/fs/cli/test/debug_test.py
index a708cc076a..29cb84243c 100644
--- a/eden/fs/cli/test/debug_test.py
+++ b/eden/fs/cli/test/debug_test.py
@@ -4,75 +4,85 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2.
 
+# pyre-strict
+
 import unittest
+from typing import List, NamedTuple, Tuple, Dict, Union
 
 from eden.fs.cli.debug import FileStatsCMD
 
 
 class DebugTest(unittest.TestCase):
-    def test_get_largest_directories_by_count(self):
+    def test_get_largest_directories_by_count(self) -> None:
+        class TestCase(NamedTuple):
+            test_input: Tuple[List[Tuple[str, int]], int]
+            test_output: List[Dict[str, Union[int, str]]]
+            msg: str
 
-        test_cases = [
-            {
-                "input": ([], 0),
-                "output": [{"path": ".", "file_count": 0}],
-                "msg": "empty directory with no minimum",
-            },
-            {
-                "input": ([], 1),
-                "output": [],
-                "msg": "empty directory with minimum of 1",
-            },
-            {
-                "input": ([("dirA/filename", 1000)], 1),
-                "output": [
+        test_cases: List[TestCase] = [
+            TestCase(
+                test_input=([], 0),
+                test_output=[{"path": ".", "file_count": 0}],
+                msg="empty directory with minimum of 1",
+            ),
+            TestCase(
+                test_input=([], 1),
+                test_output=[],
+                msg="empty directory with minimum of 1",
+            ),
+            TestCase(
+                test_input=([("dirA/filename", 1000)], 1),
+                test_output=[
                     {"path": ".", "file_count": 1},
                     {"path": "dirA", "file_count": 1},
                 ],
-                "msg": "single file with minimum of 1",
-            },
-            {
-                "input": ([("dirA/filename", 1000)], 2),
-                "output": [],
-                "msg": "single file with minimum of 2",
-            },
-            {
-                "input": ([("dirA/filename", 1000), ("dirB/filename2", 50)], 1),
-                "output": [
+                msg="single file with minimum of 1",
+            ),
+            TestCase(
+                test_input=([("dirA/filename", 1000)], 2),
+                test_output=[],
+                msg="single file with minimum of 2",
+            ),
+            TestCase(
+                test_input=([("dirA/filename", 1000), ("dirB/filename2", 50)], 1),
+                test_output=[
                     {"path": ".", "file_count": 2},
                     {"path": "dirA", "file_count": 1},
                     {"path": "dirB", "file_count": 1},
                 ],
-                "msg": "two files with minimum of 1",
-            },
-            {
-                "input": ([("dirA/filename", 1000), ("dirB/filename2", 50)], 2),
-                "output": [{"path": ".", "file_count": 2}],
-                "msg": "two files with minimum of 2",
-            },
-            {
-                "input": ([("filename", 1000), ("dirA/filename2", 50)], 1),
-                "output": [
+                msg="two files with minimum of 1",
+            ),
+            TestCase(
+                test_input=([("dirA/filename", 1000), ("dirB/filename2", 50)], 2),
+                test_output=[{"path": ".", "file_count": 2}],
+                msg="two files with minimum of 2",
+            ),
+            TestCase(
+                test_input=([("filename", 1000), ("dirA/filename2", 50)], 1),
+                test_output=[
                     {"path": ".", "file_count": 2},
                     {"path": "dirA", "file_count": 1},
                 ],
-                "msg": "file in root dir",
-            },
-            {
-                "input": ([("filename", 1000), ("dirA/dirB/dirC/filename2", 50)], 1),
-                "output": [
+                msg="file in root dir",
+            ),
+            TestCase(
+                test_input=([("filename", 1000), ("dirA/dirB/dirC/filename2", 50)], 1),
+                test_output=[
                     {"path": ".", "file_count": 2},
                     {"path": "dirA", "file_count": 1},
                     {"path": "dirA/dirB", "file_count": 1},
                     {"path": "dirA/dirB/dirC", "file_count": 1},
                 ],
-                "msg": "deeply nested file",
-            },
+                msg="deeply nested file",
+            ),
         ]
 
         for test_case in test_cases:
+            path_and_sizes, min_file_count = test_case.test_input
             self.assertEqual(
-                FileStatsCMD.get_largest_directories_by_count(*test_case["input"]),
-                test_case["output"],
-                test_case["msg"],
+                FileStatsCMD.get_largest_directories_by_count(
+                    path_and_sizes, min_file_count
+                ),
+                test_case.test_output,
+                test_case.msg,
             )
diff --git a/eden/fs/cli/test/find_eden_test.py b/eden/fs/cli/test/find_eden_test.py
index 7fdd81920d..ddfadb3f17 100644
--- a/eden/fs/cli/test/find_eden_test.py
+++ b/eden/fs/cli/test/find_eden_test.py
@@ -4,6 +4,8 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2.
 
+# pyre-strict
+
 import json
 import os
 import re
diff --git a/eden/fs/cli/test/interp_test.py b/eden/fs/cli/test/interp_test.py
index 7b9cc1d4fa..2a39398f02 100644
--- a/eden/fs/cli/test/interp_test.py
+++ b/eden/fs/cli/test/interp_test.py
@@ -4,6 +4,8 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2.
 
+# pyre-strict
+
 import configparser
 import unittest
 
@@ -11,7 +13,7 @@ from .. import configinterpolator
 
 
 class InterpolatorTest(unittest.TestCase):
-    def test_basic_subs(self):
+    def test_basic_subs(self) -> None:
         defaults = {"USER": "wez", "RECURSIVE": "a${RECURSIVE}b"}
         parser = configparser.ConfigParser(
             interpolation=configinterpolator.EdenConfigInterpolator(defaults)
diff --git a/eden/fs/cli/test/lib/fake_proc_utils.py b/eden/fs/cli/test/lib/fake_proc_utils.py
index 9f9085cee7..5704e5b09f 100644
--- a/eden/fs/cli/test/lib/fake_proc_utils.py
+++ b/eden/fs/cli/test/lib/fake_proc_utils.py
@@ -4,7 +4,7 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2.
 
-# pyre_strict
+# pyre-strict
 
 import datetime
 import errno
diff --git a/eden/fs/cli/test/lib/output.py b/eden/fs/cli/test/lib/output.py
index b2690bc712..5c6d3e8010 100644
--- a/eden/fs/cli/test/lib/output.py
+++ b/eden/fs/cli/test/lib/output.py
@@ -4,6 +4,8 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2.
 
+# pyre-strict
+
 import io
 
 import eden.fs.cli.ui
diff --git a/eden/fs/cli/test/logfile_test.py b/eden/fs/cli/test/logfile_test.py
index 1639a0432a..42b4cefd3f 100644
--- a/eden/fs/cli/test/logfile_test.py
+++ b/eden/fs/cli/test/logfile_test.py
@@ -4,6 +4,8 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2.
 
+# pyre-strict
+
 import io
 import os
 import pathlib
diff --git a/eden/fs/cli/test/mtab_test.py b/eden/fs/cli/test/mtab_test.py
index 0f379d472e..2a8a694f6b 100644
--- a/eden/fs/cli/test/mtab_test.py
+++ b/eden/fs/cli/test/mtab_test.py
@@ -4,17 +4,20 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2.
 
+# pyre-strict
+
 import unittest
+from typing import Optional
 
 from eden.fs.cli.mtab import MountInfo, parse_macos_mount_output, parse_mtab
 
 
 class MTabTest(unittest.TestCase):
     # The diffs for what is written to stdout can be large.
-    maxDiff = None
+    maxDiff: Optional[int] = None
 
-    def test_parse_mtab(self):
-        contents = """\
+    def test_parse_mtab(self) -> None:
+        contents = b"""\
 homedir.eden.com:/home109/chadaustin/public_html /mnt/public/chadaustin nfs rw,context=user_u:object_r:user_home_dir_t,relatime,vers=3,rsize=65536,wsize=65536,namlen=255,soft,nosharecache,proto=tcp6,timeo=100,retrans=2,sec=krb5i,mountaddr=2401:db00:fffe:1007:face:0000:0:4007,mountvers=3,mountport=635,mountproto=udp6,local_lock=none,addr=2401:db00:fffe:1007:0000:b00c:0:4007 0 0
 squashfuse_ll /mnt/xarfuse/uid-0/2c071047-ns-4026531840 fuse.squashfuse_ll rw,nosuid,nodev,relatime,user_id=0,group_id=0 0 0
 bogus line here
@@ -23,11 +26,11 @@ edenfs: /tmp/eden_test.4rec6drf/mounts/main fuse rw,nosuid,relatime,user_id=1386
         mount_infos = parse_mtab(contents)
         self.assertEqual(3, len(mount_infos))
         one, two, three = mount_infos
-        self.assertEqual("edenfs:", three.device)
-        self.assertEqual("/tmp/eden_test.4rec6drf/mounts/main", three.mount_point)
-        self.assertEqual("fuse", three.vfstype)
+        self.assertEqual(b"edenfs:", three.device)
+        self.assertEqual(b"/tmp/eden_test.4rec6drf/mounts/main", three.mount_point)
+        self.assertEqual(b"fuse", three.vfstype)
 
-    def test_parse_mtab_macos(self):
+    def test_parse_mtab_macos(self) -> None:
         contents = b"""\
 /dev/disk1s1 on / (apfs, local, journaled)
 devfs on /dev (devfs, local, nobrowse)
diff --git a/eden/fs/cli/test/stats_test.py b/eden/fs/cli/test/stats_test.py
index 13f896965e..f214a0fd3a 100644
--- a/eden/fs/cli/test/stats_test.py
+++ b/eden/fs/cli/test/stats_test.py
@@ -4,17 +4,20 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2.
 
+# pyre-strict
+
 import unittest
 from io import StringIO
+from typing import Optional
 
 from .. import stats_print
 from ..stats import DiagInfoCounters, get_counter_table, get_store_latency
 
 
 class StatsTest(unittest.TestCase):
-    maxDiff = None
+    maxDiff: Optional[int] = None
 
-    def test_print_heading(self):
+    def test_print_heading(self) -> None:
         expected_output = """\
                                    **********
                                    TheHeading
@@ -25,7 +28,7 @@ class StatsTest(unittest.TestCase):
         stats_print.write_heading("TheHeading", out)
         self.assertEqual(out.getvalue(), expected_output)
 
-    def test_print_latency_record(self):
+    def test_print_latency_record(self) -> None:
         matrix = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12], [13, 14, 15, 16]]
         expected_output = """\
               |      avg               1                2           3          4
@@ -39,7 +42,7 @@ access        |      p90               9               10          11         12
         stats_print.write_latency_record("access", matrix, out)
         self.assertEqual(out.getvalue(), expected_output)
 
-    def test_print_table(self):
+    def test_print_table(self) -> None:
         table = {
             "key1": [1, 2, 3, 4],
             "key2": [5, 6, 7, 8],
@@ -58,7 +61,7 @@ key4                     13             14             15             16
         stats_print.write_table(table, "SystemCall", out)
         self.assertEqual(expected_output, out.getvalue())
 
-    def test_print_table_with_shorter_header_and_key_column(self):
+    def test_print_table_with_shorter_header_and_key_column(self) -> None:
         table = {"key": [1, 2, 3, 4]}
         # Verifies the width of the first column depends on the header's and
         # key's lengths.
@@ -71,7 +74,7 @@ key                1              2              3              4
         stats_print.write_table(table, "SC", out)
         self.assertEqual(expected_output, out.getvalue())
 
-    def test_format_size(self):
+    def test_format_size(self) -> None:
         self.assertEqual("1.5 GB", stats_print.format_size(1500000000))
         # rounds up
         self.assertEqual("1.6 GB", stats_print.format_size(1590000000))
@@ -79,7 +82,7 @@ key                1              2              3              4
         self.assertEqual("12 B", stats_print.format_size(12))
         self.assertEqual("0", stats_print.format_size(0))
 
-    def test_time_formats_correctly(self):
+    def test_time_formats_correctly(self) -> None:
         self.assertEqual(stats_print.format_time(0), "0 second(s)")
         self.assertEqual(stats_print.format_time(30), "30 second(s)")
         self.assertEqual(stats_print.format_time(60), "1.0 minute(s)")
diff --git a/eden/fs/cli/test/systemd_test.py b/eden/fs/cli/test/systemd_test.py
index 39062058d6..03fe1c1a7d 100644
--- a/eden/fs/cli/test/systemd_test.py
+++ b/eden/fs/cli/test/systemd_test.py
@@ -4,6 +4,8 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2.
 
+# pyre-strict
+
 import collections
 import pathlib
 import sys
diff --git a/eden/fs/cli/test/tabulate_test.py b/eden/fs/cli/test/tabulate_test.py
index 5519155ce5..bd24870d14 100644
--- a/eden/fs/cli/test/tabulate_test.py
+++ b/eden/fs/cli/test/tabulate_test.py
@@ -4,6 +4,8 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2.
 
+# pyre-strict
+
 import unittest
 
 from eden.fs.cli.tabulate import tabulate
@@ -13,7 +15,7 @@ eol = ""
 
 
 class TabulateTest(unittest.TestCase):
-    def test_tabulate(self):
+    def test_tabulate(self) -> None:
         output = tabulate(
             ["a", "b", "c"],
             rows=[
@@ -29,7 +31,7 @@ a_1   b_1 see_1{eol}
 a_two b_2 c_2{eol}""",
         )
 
-    def test_tabulate_header_labels(self):
+    def test_tabulate_header_labels(self) -> None:
         output = tabulate(
             ["a", "b", "c"],
             rows=[
diff --git a/eden/fs/cli/test/telemetry_test.py b/eden/fs/cli/test/telemetry_test.py
index 664fdad2b6..720b439dde 100644
--- a/eden/fs/cli/test/telemetry_test.py
+++ b/eden/fs/cli/test/telemetry_test.py
@@ -4,6 +4,8 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2.
 
+# pyre-strict
+
 import json
 import math
 import typing
diff --git a/eden/fs/cli/test/top_test.py b/eden/fs/cli/test/top_test.py
index 77ef544369..a6dddd0764 100644
--- a/eden/fs/cli/test/top_test.py
+++ b/eden/fs/cli/test/top_test.py
@@ -4,6 +4,8 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2.
 
+# pyre-strict
+
 import unittest
 
 from ..top import Process, format_duration
@@ -14,22 +16,22 @@ class TopTest(unittest.TestCase):
     def setUp(self) -> None:
         self.process = Process(42, "ls", "fbsource")
 
-    def test_format_cmd(self):
+    def test_format_cmd(self) -> None:
         self.assertEqual("ls", format_cmd(b"/bin/ls"))
         self.assertEqual("'chg[worker/0]'", format_cmd(b"chg[worker/0]"))
 
-    def test_format_cmd_with_arg(self):
+    def test_format_cmd_with_arg(self) -> None:
         self.assertEqual("ls -l", format_cmd(b"/bin/ls\x00-l"), "ls -l")
         self.assertEqual("ls -l 'one two'", format_cmd(b"ls\0-l\0one two"))
 
-    def test_format_cmd_trailing_null(self):
+    def test_format_cmd_trailing_null(self) -> None:
         self.assertEqual("ls -l", format_cmd(b"ls\x00-l\x00"), "ls -l")
         self.assertEqual("ls -l ''", format_cmd(b"ls\x00-l\x00\x00"), "ls -l ''")
 
-    def test_format_mount(self):
+    def test_format_mount(self) -> None:
         self.assertEqual(format_mount("/data/users/zuck/fbsource"), "fbsource")
 
-    def test_format_duration(self):
+    def test_format_duration(self) -> None:
         self.assertEqual(format_duration(1), "1ns")
         self.assertEqual(format_duration(1 * 1000), "1us")
         self.assertEqual(format_duration(1 * 1000 * 1000), "1ms")
diff --git a/eden/fs/cli/test/util_test.py b/eden/fs/cli/test/util_test.py
index edb0d8ffb6..aa125ebca3 100644
--- a/eden/fs/cli/test/util_test.py
+++ b/eden/fs/cli/test/util_test.py
@@ -4,6 +4,8 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2.
 
+# pyre-strict
+
 import stat
 import unittest
 
diff --git a/eden/fs/cli/test/wait_for_shutdown_test.py b/eden/fs/cli/test/wait_for_shutdown_test.py
index 1c7fae7f17..a8d31fafd3 100644
--- a/eden/fs/cli/test/wait_for_shutdown_test.py
+++ b/eden/fs/cli/test/wait_for_shutdown_test.py
@@ -4,6 +4,8 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2.
 
+# pyre-strict
+
 import contextlib
 import signal
 import subprocess
@@ -43,7 +45,7 @@ class WaitForShutdownTest(unittest.TestCase):
 class AutoReapingChildProcess:
     """A child process (subprocess.Popen) which is promptly reaped."""
 
-    def __init__(self, args) -> None:
+    def __init__(self, args: typing.List[str]) -> None:
         super().__init__()
 
         self.__condition = threading.Condition()
@@ -65,29 +67,26 @@ class AutoReapingChildProcess:
         with self.__condition:
             while self.__returncode is None:
                 self.__condition.wait()
-            assert self.__returncode is not None
-            # pyre-fixme[7]: Expected `int` but got `Optional[int]`.
-            return self.__returncode
+            returncode = self.__returncode
+            assert returncode is not None
+            return returncode
 
     def __wait_for_process_start(self) -> None:
         with self.__condition:
             while self.__pid is None and self.__error is None:
                 self.__condition.wait()
-            if self.__error is not None:
-                # pyre-fixme[48]: Expression `self.__error` has type
-                #  `Optional[BaseException]` but must extend BaseException.
-                raise self.__error
+            error = self.__error
+            if error is not None:
+                raise error
             assert self.__pid is not None
 
-    def __start_thread(self, *args, **kwargs) -> None:
-        thread = threading.Thread(
-            target=self.__run_thread, args=(args, kwargs), daemon=True
-        )
+    def __start_thread(self, *args: typing.List[str]) -> None:
+        thread = threading.Thread(target=self.__run_thread, args=(args), daemon=True)
         thread.start()
 
-    def __run_thread(self, popen_args, popen_kwargs) -> None:
+    def __run_thread(self, popen_args: typing.List[str]) -> None:
         try:
-            with subprocess.Popen(*popen_args, **popen_kwargs) as process:
+            with subprocess.Popen(popen_args) as process:
                 with self.__condition:
                     self.__pid = process.pid
                     self.__condition.notify_all()