diff --git a/src/test/breakpoint_overlap.py b/src/test/breakpoint_overlap.py
index 3ca211d1efe..99d4bbd695a 100644
--- a/src/test/breakpoint_overlap.py
+++ b/src/test/breakpoint_overlap.py
@@ -12,9 +12,9 @@
     'aarch64': ArchInfo('pc'),
 }
 
-syscall_re = re.compile("`SYSCALL: <unknown-syscall--1>' \\(state:EXITING_SYSCALL\\)")
-sched_re = re.compile("`SCHED'")
-eip_re = re.compile("%s:(0x[a-f0-9]+)" % regex_info[arch].ip_name)
+syscall_re = re.compile(r'''`SYSCALL: <unknown-syscall--1>' \(state:EXITING_SYSCALL\)''')
+sched_re = re.compile(r'`SCHED')
+eip_re = re.compile(r'%s:(0x[a-f0-9]+)' % regex_info[arch].ip_name)
 
 sched_enabled = False
 eip_enabled = False
diff --git a/src/test/check_syscall_perf_interval.py b/src/test/check_syscall_perf_interval.py
index 8357f038210..7fc7797cbae 100644
--- a/src/test/check_syscall_perf_interval.py
+++ b/src/test/check_syscall_perf_interval.py
@@ -12,8 +12,8 @@
 expected_count = int(sys.argv[3])
 
 last_perfctr_value = -1
-syscall_re = re.compile("`SYSCALL: (\\w+)' \\(state:0\\)")
-perfctr_re = re.compile(counter + ":(\\d+)")
+syscall_re = re.compile(r'''`SYSCALL: (\\w+)' \\(state:0\\)''')
+perfctr_re = re.compile(counter + ':(\\d+)')
 
 while True:
     line = sys.stdin.readline()
@@ -27,7 +27,7 @@
             if m:
                 v = int(m.group(1))
                 if last_perfctr_value >= 0 and v - last_perfctr_value != expected_count:
-                    print("Mismatch: saw %d %ss between %ss (from %d to %d), expected %d" % \
+                    print('Mismatch: saw %d %ss between %ss (from %d to %d), expected %d' % \
                       (v - last_perfctr_value, counter, syscall, last_perfctr_value, v, expected_count))
                     sys.exit(1)
                 last_perfctr_value = v
diff --git a/src/test/clone_interruption_finder.py b/src/test/clone_interruption_finder.py
index d0bfcde842d..80568fcd87c 100644
--- a/src/test/clone_interruption_finder.py
+++ b/src/test/clone_interruption_finder.py
@@ -1,8 +1,8 @@
 import sys
 import re
 
-syscall_re = re.compile("`SIGNAL: ")
-time_re = re.compile("global_time:(\d+)")
+syscall_re = re.compile('`SIGNAL: ')
+time_re = re.compile(r'global_time:(\d+)')
 futex_time = 999999999
 
 while True:
diff --git a/src/test/elapsed_time.py b/src/test/elapsed_time.py
index 5c04e46423c..92ac609d017 100644
--- a/src/test/elapsed_time.py
+++ b/src/test/elapsed_time.py
@@ -15,8 +15,7 @@
 elapsed_time = float(last_match().group(0))
 sleep_time = 1.0
 if elapsed_time < sleep_time:
-    failed("ERROR ... The reported elapsed time after sleeping for " +
-           "{sleep_time} (s) was {elapsed_time}".format(
-               sleep_time=sleep_time, elapsed_time=elapsed_time))
+    failed('ERROR ... The reported elapsed time after sleeping for ' +
+           f'{sleep_time} (s) was {elapsed_time}')
 
 ok()
diff --git a/src/test/gdb_qpasssignals.py b/src/test/gdb_qpasssignals.py
index 1a703ef130d..ba4d3830d1c 100644
--- a/src/test/gdb_qpasssignals.py
+++ b/src/test/gdb_qpasssignals.py
@@ -1,16 +1,16 @@
 from util import *
 
-send_gdb("handle SIGURG noprint nostop pass")
-send_gdb("handle SIGKILL stop")
+send_gdb('handle SIGURG noprint nostop pass')
+send_gdb('handle SIGKILL stop')
 
-send_gdb("c")
+send_gdb('c')
 
 
-expect_rr("XIT-END")
+expect_rr('XIT-END')
 
-send_gdb("b main")
-expect_gdb("Breakpoint 1")
-send_gdb("reverse-continue")
+send_gdb('b main')
+expect_gdb('Breakpoint 1')
+send_gdb('reverse-continue')
 
-expect_gdb("Breakpoint 1")
+expect_gdb('Breakpoint 1')
 ok()
\ No newline at end of file
diff --git a/src/test/history.py b/src/test/history.py
index 922a7f9d2bb..6b22078b7b4 100644
--- a/src/test/history.py
+++ b/src/test/history.py
@@ -15,7 +15,7 @@
 expect_gdb('i=4')
 
 send_gdb('forward')
-expect_gdb("Can't go forward. No more history entries.")
+expect_gdb('Can\'t go forward. No more history entries.')
 
 send_gdb('back')
 expect_gdb('i=3')
@@ -34,7 +34,7 @@
 send_gdb('c')
 expect_gdb('i=1')
 send_gdb('forward')
-expect_gdb("Can't go forward. No more history entries.")
+expect_gdb('Can\'t go forward. No more history entries.')
 
 send_gdb('back')
 expect_gdb('i=0')
diff --git a/src/test/read_big_struct.py b/src/test/read_big_struct.py
index 046dc42387e..4f71d61d5a8 100644
--- a/src/test/read_big_struct.py
+++ b/src/test/read_big_struct.py
@@ -10,6 +10,6 @@
 expect_gdb('(rr)')
 
 send_gdb('p big')
-expect_gdb("bytes = 'Z'")
+expect_gdb('bytes = \'Z\'')
 
 ok()
diff --git a/src/test/seekticks.py b/src/test/seekticks.py
index f5a6f7b89f2..c65f825ac27 100644
--- a/src/test/seekticks.py
+++ b/src/test/seekticks.py
@@ -33,24 +33,24 @@
 if ticks3 <= ticks2:
     failed('ERROR ... "when-ticks" failed to advance')
 
-send_gdb("seek-ticks %d" % ticks2)
-expect_gdb("Program stopped.")
+send_gdb(f'seek-ticks {ticks2}')
+expect_gdb('Program stopped.')
 send_gdb('when-ticks')
 expect_gdb(re.compile(r'Current tick: (\d+)'))
 ticks4 = int(last_match().group(1))
 if ticks4 != ticks2:
     failed('ERROR: Failed to seek back to ticks2')
 
-send_gdb("seek-ticks %d" % ticks)
-expect_gdb("Program stopped.")
+send_gdb(f'seek-ticks {ticks}')
+expect_gdb('Program stopped.')
 send_gdb('when-ticks')
 expect_gdb(re.compile(r'Current tick: (\d+)'))
 ticks5 = int(last_match().group(1))
 if ticks5 != ticks:
     failed('ERROR: Failed to seek back to ticks')
 
-send_gdb("seek-ticks %d" % ticks2)
-expect_gdb("Program stopped.")
+send_gdb(f'seek-ticks {ticks2}')
+expect_gdb('Program stopped.')
 send_gdb('when-ticks')
 expect_gdb(re.compile(r'Current tick: (\d+)'))
 ticks6 = int(last_match().group(1))
@@ -64,13 +64,13 @@
 
 for i in range(len(tests)):
     ticks7 = tests[i]
-    send_gdb("seek-ticks %d" % ticks7)
-    expect_gdb("Program stopped.")
+    send_gdb(f'seek-ticks {ticks7}')
+    expect_gdb('Program stopped.')
     send_gdb('when-ticks')
     expect_gdb(re.compile(r'Current tick: (\d+)'))
     ticks8 = int(last_match().group(1))
     if ticks8 != ticks7:
-        failed("ERROR: seek-ticks didn't go to correct tick on test %d" % i)
+        failed(f'ERROR: seek-ticks didn\'t go to correct tick on test {i}')
 
 send_gdb('seek-ticks 2000000000')
 expect_gdb('No event found matching specified ticks target')
diff --git a/src/test/signal_checkpoint.py b/src/test/signal_checkpoint.py
index a6a30de7f58..ab3e9cb0186 100644
--- a/src/test/signal_checkpoint.py
+++ b/src/test/signal_checkpoint.py
@@ -12,7 +12,7 @@
 send_gdb('c')
 expect_gdb('Breakpoint 1, sighandler')
 
-send_gdb("restart 1");
+send_gdb('restart 1');
 send_gdb('c')
 expect_gdb('Breakpoint 1, sighandler')
 
diff --git a/src/test/tick0.py b/src/test/tick0.py
index 2e421435da2..4661e606ea2 100644
--- a/src/test/tick0.py
+++ b/src/test/tick0.py
@@ -23,8 +23,8 @@ def get_when():
 if ticks_end < 99999:
     failed('End ticks too low')
 
-send_gdb("seek-ticks %d" % ticks_start)
-expect_gdb("Program stopped.")
+send_gdb(f'seek-ticks {ticks_start}')
+expect_gdb('Program stopped.')
 (event_exp, ticks_from_end) = get_when()
 if ticks_from_end != ticks_start:
     failed('ERROR: Failed to seek back to tick 0 from end')
@@ -37,8 +37,8 @@ def get_when():
     expect_gdb(re.compile(r'(Thread \d+|Program) stopped'))
     
     
-    send_gdb("seek-ticks %d" % ticks_start)
-    expect_gdb("Program stopped.")
+    send_gdb(f'seek-ticks {ticks_start}')
+    expect_gdb('Program stopped.')
     
     (event, ticks) = get_when()
     if ticks != 0:
diff --git a/src/test/util.py b/src/test/util.py
index 96db8dd9147..f6e2993853a 100644
--- a/src/test/util.py
+++ b/src/test/util.py
@@ -58,11 +58,11 @@ def interrupt_gdb():
 
 def send_gdb(what):
     assert debugger_type == 'GDB'
-    send(child, "%s\n"%what)
+    send(child, f'{what}\n')
 
 def send_lldb(what):
     assert debugger_type == 'LLDB'
-    send(child, "%s\n"%what)
+    send(child, f'{what}\n')
 
 # Restarts and continues execution
 def restart_replay(event=0):
@@ -106,21 +106,21 @@ def backtrace():
 
 def expect_breakpoint_stop(number):
     if debugger_type == 'GDB':
-        expect_debugger("Breakpoint %d"%number)
+        expect_debugger(f'Breakpoint {number}')
     else:
-        expect_debugger("stop reason = breakpoint %d"%number)
+        expect_debugger(f'stop reason = breakpoint {number}')
 
 def expect_watchpoint_stop(number):
     if debugger_type == 'GDB':
-        expect_debugger("atchpoint %d"%number)
+        expect_debugger(f'atchpoint {number}')
     else:
-        expect_debugger("stop reason = watchpoint %d"%number)
+        expect_debugger(f'stop reason = watchpoint {number}')
 
 def expect_signal_stop(signal_name):
     if debugger_type == 'GDB':
-        expect_debugger(f"received signal {signal_name}")
+        expect_debugger(f'received signal {signal_name}')
     else:
-        expect_debugger(f"received signal: {signal_name}")
+        expect_debugger(f'received signal: {signal_name}')
 
 def set_breakpoint_commands(number, commands):
     if debugger_type == 'GDB':
@@ -154,10 +154,10 @@ def expect_threads(num_threads, selected_thread):
 
 def select_thread(index):
     if debugger_type == 'GDB':
-        send_gdb(f"thread {index}")
+        send_gdb(f'thread {index}')
         expect_debugger(f'Switching to thread {index} ')
     else:
-        send_lldb(f"thread select {index}")
+        send_lldb(f'thread select {index}')
         expect_debugger(f'thread #{index}')
 
 def scheduler_locking_on():
@@ -205,7 +205,7 @@ def clean_up():
             child = None
         except Exception as e:
             if iterations < 5:
-                print("close() failed with '%s', retrying..."%e)
+                print(f'close() failed with "{e}", retrying...')
                 iterations = iterations + 1
             else:
                 child = None
@@ -214,13 +214,13 @@ def expect(prog, what):
     try:
         prog.expect(what)
     except Exception as e:
-        failed('expecting "%s"'% (what), e)
+        failed(f'expecting "{what}"', e)
 
 def send(prog, what):
     try:
         prog.send(what)
     except Exception as e:
-        failed('sending "%s"'% (what), e)
+        failed(f'sending "{what}"', e)
 
 def set_up():
     global child