diff --git a/tests/fuzzing/fuzz.nims b/tests/fuzzing/fuzz.nims
index daa1aba..2032c4e 100644
--- a/tests/fuzzing/fuzz.nims
+++ b/tests/fuzzing/fuzz.nims
@@ -1,36 +1,7 @@
-import strformat, strutils
+import ./fuzz_helpers
 
-# Dependencies:
-# - afl fuzzing: afl and gcc or clang/llvm
-# - libFuzzer fuzzing: libFuzzer and clang/llvm
-# - in afl experimental modes clang/llvm is also required
-
-# TODO:
-# - switch clang / gcc option for afl
-# - afl init and persistent modes
-# - parallel fuzzing
-# - custom generate test cases from this script?
-# - rerun testcases option (or create tests from failed cases)?
-# - better cmd line parsing & and more options
-
-const aflGcc = "--cc=gcc " &
-                "--gcc.exe=afl-gcc " &
-                "--gcc.linkerexe=afl-gcc"
-const aflClang = "--cc=clang " &
-                  "--clang.exe=afl-clang " &
-                  "--clang.linkerexe=afl-clang"
-const aflClangFast = "--cc=clang " &
-                      "--clang.exe=afl-clang-fast " &
-                      "--clang.linkerexe=afl-clang-fast"
-const libFuzzerClang = "--cc=clang " &
-                        "--passC='-fsanitize=fuzzer,address' " &
-                        "--passL='-fsanitize=fuzzer,address'"
-# Can also test in debug mode obviously, but might be slower
-# Can turn on more logging, in case of libFuzzer it will get very verbose though
-const defaultFlags = "-d:release -d:chronicles_log_level=fatal " &
-                      "--hints:off --warnings:off --verbosity:0"
-const inputDir = "input" # dir for input samples
-const resultsDir = "results" # results dir (for afl)
+# TODO: get this some nice cmd line options when confutils works for nimscript
+# or if we want to put this in a nim application instead of script
 
 if paramCount() < 3:
   echo "Usage: nim fuzz.nims FUZZER TARGET"
@@ -45,45 +16,13 @@ if not fileExists(targetPath):
   echo "Target file does not exist"
   quit 1
 
-let splitFile = targetPath.rsplit("/", 1)
-let workDir = splitFile[0]
-let targetNimFile = splitFile[1]
-var target = targetNimFile
-target.removeSuffix(".nim")
-cd workDir
-
 case fuzzer
 of "afl":
-  let aflOptions = &"-d:afl -d:noSignalHandler {aflGcc}"
-  let compileCmd = &"nim c {defaultFlags} {aflOptions} {target}"
-  exec compileCmd
-
-  if not dirExists(inputDir):
-    # create a input dir with one 0 file for afl
-    mkDir(inputDir)
-    withDir inputDir: exec "echo '0' > test"
-
-  var fuzzCmd: string
-  # if there is an output dir already, continue fuzzing from previous run
-  if not dirExists(resultsDir):
-    fuzzCmd = &"afl-fuzz -i {inputDir} -o {resultsDir} -M fuzzer01 -- ./{target}"
-  else:
-    fuzzCmd = &"afl-fuzz -i - -o {resultsDir} -M fuzzer01 -- ./{target}"
-  exec fuzzCmd
-
+  runFuzzer(targetPath, afl)
 of "libFuzzer":
-  let libFuzzerOptions = &"--noMain {libFuzzerClang}"
-  let compileCmd = &"nim c {defaultFlags} {libFuzzerOptions} {target}"
-  exec compileCmd
-
-  if not dirExists(inputDir):
-    # libFuzzer is OK with empty input dir
-    mkDir(inputDir)
-
-  # TODO: could use {resultsDir} of afl here also to reuse as corpus
-  exec &"./{target} {inputDir}"
+  runFuzzer(targetPath, libFuzzer)
 
 else:
   echo "Invalid fuzzer option: ", fuzzer
   echo "Fuzzer options are afl or libFuzzer"
-  quit 1
\ No newline at end of file
+  quit 1
diff --git a/tests/fuzzing/fuzz_helpers.nim b/tests/fuzzing/fuzz_helpers.nim
new file mode 100644
index 0000000..8af34f7
--- /dev/null
+++ b/tests/fuzzing/fuzz_helpers.nim
@@ -0,0 +1,101 @@
+import strformat, strutils
+
+# Dependencies:
+# - afl fuzzing: afl and gcc or clang/llvm
+# - libFuzzer fuzzing: libFuzzer and clang/llvm
+# - in afl experimental modes clang/llvm is also required
+
+# TODO:
+# - switch clang / gcc option for afl
+# - afl init and persistent modes
+# - parallel fuzzing options
+# - custom generate test cases from this script?
+# - rerun testcases option (or create tests from failed cases)
+# - currently not cross platform
+# - ...
+
+const
+  aflGcc = "--cc=gcc " &
+           "--gcc.exe=afl-gcc " &
+           "--gcc.linkerexe=afl-gcc"
+  aflClang = "--cc=clang " &
+             "--clang.exe=afl-clang " &
+             "--clang.linkerexe=afl-clang"
+  aflClangFast = "--cc=clang " &
+                 "--clang.exe=afl-clang-fast " &
+                 "--clang.linkerexe=afl-clang-fast"
+  libFuzzerClang = "--cc=clang " &
+                   "--passC='-fsanitize=fuzzer,address' " &
+                   "--passL='-fsanitize=fuzzer,address'"
+# Can also test in debug mode obviously, but might be slower
+# Can turn on more logging, in case of libFuzzer it will get very verbose though
+  defaultFlags = "-d:release -d:chronicles_log_level=fatal "# &
+                #  "--hints:off --warnings:off --verbosity:0"
+
+type
+  Fuzzer* = enum
+    afl,
+    libFuzzer
+
+  Compiler* = enum
+    gcc = aflGcc,
+    clang = aflClang,
+    clangFast = aflClangFast
+
+proc aflCompile*(target: string, c: Compiler) =
+  let aflOptions = &"-d:standalone -d:noSignalHandler {$c}"
+  let compileCmd = &"nim c {defaultFlags} {aflOptions} {target}"
+  exec compileCmd
+
+proc aflExec*(target: string, inputDir: string, resultsDir: string,
+    cleanStart = false) =
+  if not dirExists(inputDir):
+    # create a input dir with one 0 file for afl
+    mkDir(inputDir)
+    withDir inputDir: exec "echo '0' > test"
+
+  var fuzzCmd: string
+  # if there is an output dir already, continue fuzzing from previous run
+  if (not dirExists(resultsDir)) or cleanStart:
+    fuzzCmd = &"afl-fuzz -i {inputDir} -o {resultsDir} -M fuzzer01 -- ./{target}"
+  else:
+    fuzzCmd = &"afl-fuzz -i - -o {resultsDir} -M fuzzer01 -- ./{target}"
+  exec fuzzCmd
+
+proc libFuzzerCompile*(target: string) =
+  let libFuzzerOptions = &"--noMain {libFuzzerClang}"
+  let compileCmd = &"nim c {defaultFlags} {libFuzzerOptions} {target}"
+  exec compileCmd
+
+proc libFuzzerExec*(target: string, corpusDir: string) =
+  if not dirExists(corpusDir):
+    # libFuzzer is OK when starting with empty corpus dir
+    mkDir(corpusDir)
+
+  exec &"./{target} {corpusDir}"
+
+proc getDir*(path: string): string =
+  # TODO: This is not platform friendly at all.
+  let splitFile = path.rsplit("/", 1)
+  result = splitFile[0]
+
+proc getTarget*(path: string): string =
+  # TODO: error handling
+  result = path
+  result.removeSuffix(".nim")
+
+proc runFuzzer*(targetPath: string, fuzzer: Fuzzer) =
+  let
+    path = getDir(targetPath)
+    target = getTarget(targetPath)
+  case fuzzer
+  of afl:
+    aflCompile(targetPath, gcc)
+    aflExec(target, path & "/input", path & "/results")
+
+  of libFuzzer:
+    libFuzzerCompile(targetPath)
+    # Note: Lets not mix afl input with libFuzzer corpus default. This can have
+    # consequences on speed for afl. Better to look into merging afl results &
+    # libFuzzer corpus.
+    libFuzzerExec(target, path & "/corpus")