diff --git a/src/pk_core.c b/src/pk_core.c
index 071f3d1..40e34b1 100644
--- a/src/pk_core.c
+++ b/src/pk_core.c
@@ -1315,7 +1315,7 @@ bool varContains(PKVM* vm, Var elem, Var container) {
     case OBJ_INST:
       TODO;
   }
-
+  UNREACHABLE();
 }
 
 // Here we're switching the FNV-1a hash value of the name (cstring). Which is
diff --git a/tests/benchmark/benchmarks.py b/tests/benchmark/benchmarks.py
deleted file mode 100644
index 861d184..0000000
--- a/tests/benchmark/benchmarks.py
+++ /dev/null
@@ -1,54 +0,0 @@
-import subprocess, os, sys
-import json, re
-from os.path import join
-
-## FIXME: this file needs to be refactored.
-
-## All benchmark files. ## TODO: pass args for iterations.
-benchmarks = {
-  "factors"      : ['.pk', '.py', '.rb', '.js', '.wren'],
-  "fib"          : ['.pk', '.py', '.rb', '.js', '.wren'],
-  "list"         : ['.pk', '.py', '.rb', '.js'],
-  "loop"         : ['.pk', '.py', '.rb', '.js', '.wren'],
-  "primes"       : ['.pk', '.py', '.rb', '.js', '.wren'],
-}
-
-def main():
-  run_all_benchmarks()
-
-def run_all_benchmarks():
-  print_title("BENCHMARKS")
-
-  def get_interpreter(file):
-    if file.endswith('.pk'  ) : return 'pocket'
-    if file.endswith('.py'  ) : return 'python'
-    if file.endswith('.rb'  ) : return 'ruby'
-    if file.endswith('.wren') : return 'wren'
-    if file.endswith('.js'  ) : return 'node'
-    assert False
-
-  for bm_name in benchmarks:
-    print(bm_name + ":")
-    for ext in benchmarks[bm_name]:
-      file = join(bm_name, bm_name + ext)
-      interpreter = get_interpreter(file)
-      print('  %10s: '%interpreter, end=''); sys.stdout.flush()
-      result = run_command([interpreter, file])
-      time = re.findall(r'elapsed:\s*([0-9\.]+)\s*s',
-                result.stdout.decode('utf8'),
-                re.MULTILINE)
-      assert len(time) == 1, r'elapsed:\s*([0-9\.]+)\s*s --> no mach found.'
-      print('%10ss'%time[0])
-
-def run_command(command):
-  return subprocess.run(command,
-                          stdout=subprocess.PIPE,
-                          stderr=subprocess.PIPE)
-
-def print_title(title):
-  print("--------------------------------")
-  print(" %s " % title)
-  print("--------------------------------")
-  
-if __name__ == '__main__':
-  main()
diff --git a/tests/benchmarks/benchmarks.py b/tests/benchmarks/benchmarks.py
new file mode 100644
index 0000000..21918e6
--- /dev/null
+++ b/tests/benchmarks/benchmarks.py
@@ -0,0 +1,156 @@
+#!python
+## Copyright (c) 2020-2021 Thakee Nathees
+## Distributed Under The MIT License
+
+import subprocess, re, os, sys, platform
+from os.path import join, abspath, dirname, relpath
+from shutil import which
+
+## The absolute path of this file, when run as a script.
+## This file is not intended to be included in other files at the moment.
+THIS_PATH = abspath(dirname(__file__))
+
+## Map from systems to the relative pocket binary path.
+SYSTEM_TO_BINARY_PATH = {
+  "Windows": "..\\..\\build\\release\\bin\\pocket.exe",
+  "Linux"  : "../../build/release/pocket",
+  "Darwin" : "../../build/release/pocket",
+}
+
+## A list of benchmark directories, relative to THIS_PATH
+BENCHMARKS = (
+  "factors",
+  "fib",
+  "list",
+  "loop",
+  "primes",
+)
+
+## Map from file extension to it's interpreter, Will be updated.
+INTERPRETERS = {
+  '.pk'   : None,
+  '.wren' : None,
+  '.rb'   : None,
+  '.rb'   : None,
+}
+
+def main():
+  update_interpreters()
+  run_all_benchmarsk()
+
+## ----------------------------------------------------------------------------
+## RUN ALL BENCHMARKS
+## ----------------------------------------------------------------------------
+
+def run_all_benchmarsk():
+  for benchmark in BENCHMARKS:
+    print_title(benchmark)
+    dir = join(THIS_PATH, benchmark)
+    for file in os.listdir(dir):
+      file = abspath(join(dir, file))
+      
+      ext = get_ext(file) ## File extension.
+      if ext not in INTERPRETERS: continue
+      lang, interp = INTERPRETERS[ext]
+      if not interp: continue
+      
+      print("%-10s : "%lang, end=''); sys.stdout.flush()
+      result = _run_command([interp, file])
+      time = re.findall(r'elapsed:\s*([0-9\.]+)\s*s',
+                result.stdout.decode('utf8'),
+                re.MULTILINE)
+
+      if len(time) != 1:
+        print() # Skip the line.
+        error_exit(r'elapsed:\s*([0-9\.]+)\s*s --> no mach found.')
+      print('%.6fs'%float(time[0]))
+  pass
+
+def _run_command(command):
+  return subprocess.run(command,
+                        stdout=subprocess.PIPE,
+                        stderr=subprocess.PIPE)
+
+## ----------------------------------------------------------------------------
+## UPDATE INTERPRETERS
+## ----------------------------------------------------------------------------
+
+def update_interpreters():
+  pocket = _get_pocket_binary()
+  python = 'python' if platform.system() == 'Windows' else 'python3'
+  print_title("CHECKING FOR INTERPRETERS")
+  global INTERPRETERS
+  INTERPRETERS['.pk']   = _find_interp('pocketlang', pocket)
+  INTERPRETERS['.wren'] = _find_interp('wren',       'wren')
+  INTERPRETERS['.rb']   = _find_interp('ruby',       'ruby')
+  INTERPRETERS['.py']   = _find_interp('python',     python)
+  INTERPRETERS['.js']   = _find_interp('javascript', 'node')  
+
+## This will return the path of the pocket binary (on different platforms).
+## The debug version of it for enabling the assertions.
+def _get_pocket_binary():
+  system = platform.system()
+  if system not in SYSTEM_TO_BINARY_PATH:
+    error_exit("Unsupported platform %s" % system)
+
+  pocket = abspath(join(THIS_PATH, SYSTEM_TO_BINARY_PATH[system]))
+  if not os.path.exists(pocket):
+    error_exit("Pocket interpreter not found at: '%s'" % pocket)
+
+  return pocket
+
+## Find and return the interpreter from the path.
+## as (lang, interp) tuple.
+def _find_interp(lang, interpreter):
+  print('%-25s' % ('Searching for %s ' % lang), end='')
+  sys.stdout.flush()
+  if which(interpreter):
+    print_success('-- found')
+    return (lang, interpreter)
+  print_warning('-- not found (skipped)')
+  return (lang, None)
+
+## Return the extension from the file name.
+def get_ext(file_name):
+  period = file_name.rfind('.'); assert period > 0
+  return file_name[period:]
+
+## ----------------------------------------------------------------------------
+## PRINT FUNCTIONS
+## ----------------------------------------------------------------------------
+
+def print_title(title):
+  print("----------------------------------")
+  print(" %s " % title)
+  print("----------------------------------")
+
+## ANSI color codes to print messages.
+COLORS = {
+  'GREEN'     : '\u001b[32m',
+  'YELLOW'    : '\033[93m',
+  'RED'       : '\u001b[31m',
+  'UNDERLINE' : '\033[4m' ,
+  'END'       : '\033[0m' ,
+}
+
+## Prints a warning message to stdour.
+def print_warning(msg):
+  os.system('') ## This will enable ANSI codes in windows terminal.
+  for line in msg.splitlines():
+    print(COLORS['YELLOW'] + line + COLORS['END'])
+
+## print success message to stdout.
+def print_success(msg):
+  os.system('') ## This will enable ANSI codes in windows terminal.
+  for line in msg.splitlines():
+    print(COLORS['GREEN'] + line + COLORS['END'])
+
+## prints an error message to stderr and exit
+## immediately.
+def error_exit(msg):
+  os.system('') ## This will enable ANSI codes in windows terminal.
+  print(COLORS['RED'] + 'Error: ' + msg + COLORS['END'], end='')
+  sys.exit(1)
+  
+if __name__ == '__main__':
+  main()
diff --git a/tests/benchmark/factors/factors.js b/tests/benchmarks/factors/factors.js
similarity index 100%
rename from tests/benchmark/factors/factors.js
rename to tests/benchmarks/factors/factors.js
diff --git a/tests/benchmark/factors/factors.pk b/tests/benchmarks/factors/factors.pk
similarity index 100%
rename from tests/benchmark/factors/factors.pk
rename to tests/benchmarks/factors/factors.pk
diff --git a/tests/benchmark/factors/factors.py b/tests/benchmarks/factors/factors.py
similarity index 100%
rename from tests/benchmark/factors/factors.py
rename to tests/benchmarks/factors/factors.py
diff --git a/tests/benchmark/factors/factors.rb b/tests/benchmarks/factors/factors.rb
similarity index 100%
rename from tests/benchmark/factors/factors.rb
rename to tests/benchmarks/factors/factors.rb
diff --git a/tests/benchmark/factors/factors.wren b/tests/benchmarks/factors/factors.wren
similarity index 100%
rename from tests/benchmark/factors/factors.wren
rename to tests/benchmarks/factors/factors.wren
diff --git a/tests/benchmark/fib/fib.js b/tests/benchmarks/fib/fib.js
similarity index 100%
rename from tests/benchmark/fib/fib.js
rename to tests/benchmarks/fib/fib.js
diff --git a/tests/benchmark/fib/fib.pk b/tests/benchmarks/fib/fib.pk
similarity index 100%
rename from tests/benchmark/fib/fib.pk
rename to tests/benchmarks/fib/fib.pk
diff --git a/tests/benchmark/fib/fib.py b/tests/benchmarks/fib/fib.py
similarity index 100%
rename from tests/benchmark/fib/fib.py
rename to tests/benchmarks/fib/fib.py
diff --git a/tests/benchmark/fib/fib.rb b/tests/benchmarks/fib/fib.rb
similarity index 100%
rename from tests/benchmark/fib/fib.rb
rename to tests/benchmarks/fib/fib.rb
diff --git a/tests/benchmark/fib/fib.wren b/tests/benchmarks/fib/fib.wren
similarity index 100%
rename from tests/benchmark/fib/fib.wren
rename to tests/benchmarks/fib/fib.wren
diff --git a/tests/benchmark/list/list.js b/tests/benchmarks/list/list.js
similarity index 100%
rename from tests/benchmark/list/list.js
rename to tests/benchmarks/list/list.js
diff --git a/tests/benchmark/list/list.pk b/tests/benchmarks/list/list.pk
similarity index 100%
rename from tests/benchmark/list/list.pk
rename to tests/benchmarks/list/list.pk
diff --git a/tests/benchmark/list/list.py b/tests/benchmarks/list/list.py
similarity index 100%
rename from tests/benchmark/list/list.py
rename to tests/benchmarks/list/list.py
diff --git a/tests/benchmark/list/list.rb b/tests/benchmarks/list/list.rb
similarity index 100%
rename from tests/benchmark/list/list.rb
rename to tests/benchmarks/list/list.rb
diff --git a/tests/benchmark/loop/loop.js b/tests/benchmarks/loop/loop.js
similarity index 100%
rename from tests/benchmark/loop/loop.js
rename to tests/benchmarks/loop/loop.js
diff --git a/tests/benchmark/loop/loop.pk b/tests/benchmarks/loop/loop.pk
similarity index 100%
rename from tests/benchmark/loop/loop.pk
rename to tests/benchmarks/loop/loop.pk
diff --git a/tests/benchmark/loop/loop.py b/tests/benchmarks/loop/loop.py
similarity index 100%
rename from tests/benchmark/loop/loop.py
rename to tests/benchmarks/loop/loop.py
diff --git a/tests/benchmark/loop/loop.rb b/tests/benchmarks/loop/loop.rb
similarity index 100%
rename from tests/benchmark/loop/loop.rb
rename to tests/benchmarks/loop/loop.rb
diff --git a/tests/benchmark/loop/loop.wren b/tests/benchmarks/loop/loop.wren
similarity index 100%
rename from tests/benchmark/loop/loop.wren
rename to tests/benchmarks/loop/loop.wren
diff --git a/tests/benchmark/primes/primes.js b/tests/benchmarks/primes/primes.js
similarity index 100%
rename from tests/benchmark/primes/primes.js
rename to tests/benchmarks/primes/primes.js
diff --git a/tests/benchmark/primes/primes.pk b/tests/benchmarks/primes/primes.pk
similarity index 100%
rename from tests/benchmark/primes/primes.pk
rename to tests/benchmarks/primes/primes.pk
diff --git a/tests/benchmark/primes/primes.py b/tests/benchmarks/primes/primes.py
similarity index 100%
rename from tests/benchmark/primes/primes.py
rename to tests/benchmarks/primes/primes.py
diff --git a/tests/benchmark/primes/primes.rb b/tests/benchmarks/primes/primes.rb
similarity index 100%
rename from tests/benchmark/primes/primes.rb
rename to tests/benchmarks/primes/primes.rb
diff --git a/tests/benchmark/primes/primes.wren b/tests/benchmarks/primes/primes.wren
similarity index 100%
rename from tests/benchmark/primes/primes.wren
rename to tests/benchmarks/primes/primes.wren
diff --git a/tests/benchmark/toc/toc.pk b/tests/benchmarks/toc/toc.pk
similarity index 100%
rename from tests/benchmark/toc/toc.pk
rename to tests/benchmarks/toc/toc.pk