diff --git a/cmd/tools/vdoc/tests/vdoc_file_test.v b/cmd/tools/vdoc/tests/vdoc_file_test.v
index 4f0c393928..6e99f8cfaf 100644
--- a/cmd/tools/vdoc/tests/vdoc_file_test.v
+++ b/cmd/tools/vdoc/tests/vdoc_file_test.v
@@ -115,18 +115,20 @@ fn test_out_path() {
 }
 
 fn print_compare(expected string, found string) {
-	diff_cmd := diff.find_working_diff_command() or { return }
 	println(term.red('FAIL'))
 	println('============')
-	println('expected:')
-	println(expected)
-	println('============')
-	println('found:')
-	println(found)
-	println('============\n')
-	println('diff:')
-	println(diff.color_compare_strings(diff_cmd, rand.ulid(), expected, found))
-	println('============\n')
+	if diff_ := diff.compare_text(expected, found) {
+		println('diff:')
+		println(diff_)
+		println('============\n')
+	} else {
+		println('expected:')
+		println(expected)
+		println('============')
+		println('found:')
+		println(found)
+		println('============\n')
+	}
 }
 
 @[params]
diff --git a/vlib/v/fmt/fmt_bin2v_test.v b/vlib/v/fmt/fmt_bin2v_test.v
index f36ace474d..4596ae7839 100644
--- a/vlib/v/fmt/fmt_bin2v_test.v
+++ b/vlib/v/fmt/fmt_bin2v_test.v
@@ -15,11 +15,6 @@ const fpref = &pref.Preferences{
 }
 
 fn test_bin2v_formatting() {
-	diff_cmd := diff.find_working_diff_command() or { '' }
-	if diff_cmd == '' {
-		eprintln('>> sorry, but no working "diff" CLI command can be found')
-		exit(0)
-	}
 	os.mkdir_all(tmpfolder)!
 	defer {
 		os.rmdir_all(tmpfolder) or {}
@@ -33,8 +28,8 @@ fn test_bin2v_formatting() {
 	expected_ocontent := os.read_file(b2v_keep_path)!
 	if expected_ocontent != result_ocontent {
 		vfmt_result_file := os.join_path(tmpfolder, 'vfmt_run_over_${ifilename}')
-		os.write_file(vfmt_result_file, result_ocontent) or { panic(err) }
-		eprintln(diff.color_compare_files(diff_cmd, b2v_keep_path, vfmt_result_file))
+		os.write_file(vfmt_result_file, result_ocontent)!
+		println(diff.compare_files(b2v_keep_path, vfmt_result_file)!)
 		exit(1)
 	} else {
 		assert true
diff --git a/vlib/v/fmt/fmt_keep_test.v b/vlib/v/fmt/fmt_keep_test.v
index d574e34649..088fbe14d1 100644
--- a/vlib/v/fmt/fmt_keep_test.v
+++ b/vlib/v/fmt/fmt_keep_test.v
@@ -30,7 +30,6 @@ fn run_fmt(mut input_files []string) {
 	mut fmt_bench := benchmark.new_benchmark()
 	fmt_bench.set_total_expected_steps(input_files.len + 1)
 	tmpfolder := os.temp_dir()
-	diff_cmd := diff.find_working_diff_command() or { '' }
 	for istep, ipath in input_files {
 		fmt_bench.cstep = istep + 1
 		fmt_bench.step()
@@ -45,13 +44,9 @@ fn run_fmt(mut input_files []string) {
 		if expected_ocontent != result_ocontent {
 			fmt_bench.fail()
 			eprintln(fmt_bench.step_message_fail('file ${ipath} after formatting, does not look as expected.'))
-			if diff_cmd == '' {
-				eprintln('>> sorry, but no working "diff" CLI command can be found')
-				continue
-			}
 			vfmt_result_file := os.join_path(tmpfolder, 'vfmt_run_over_${os.file_name(ipath)}')
 			os.write_file(vfmt_result_file, result_ocontent) or { panic(err) }
-			eprintln(diff.color_compare_files(diff_cmd, ipath, vfmt_result_file))
+			println(diff.compare_files(ipath, vfmt_result_file) or { err.msg() })
 			continue
 		}
 		fmt_bench.ok()
diff --git a/vlib/v/fmt/fmt_test.v b/vlib/v/fmt/fmt_test.v
index 068434601e..8528fc5cc1 100644
--- a/vlib/v/fmt/fmt_test.v
+++ b/vlib/v/fmt/fmt_test.v
@@ -21,7 +21,6 @@ fn run_fmt(mut input_files []string) {
 	fmt_message := 'vfmt tests'
 	eprintln(term.header(fmt_message, '-'))
 	tmpfolder := os.temp_dir()
-	diff_cmd := diff.find_working_diff_command() or { '' }
 	assert input_files.len > 0
 	input_files = vtest.filter_vtest_only(input_files)
 	if input_files.len == 0 {
@@ -51,13 +50,9 @@ fn run_fmt(mut input_files []string) {
 		if expected_ocontent != result_ocontent {
 			fmt_bench.fail()
 			eprintln(fmt_bench.step_message_fail('file ${ipath} after formatting, does not look as expected.'))
-			if diff_cmd == '' {
-				eprintln('>> sorry, but no working "diff" CLI command can be found')
-				continue
-			}
 			vfmt_result_file := os.join_path(tmpfolder, 'vfmt_run_over_${os.file_name(ipath)}')
 			os.write_file(vfmt_result_file, result_ocontent) or { panic(err) }
-			eprintln(diff.color_compare_files(diff_cmd, opath, vfmt_result_file))
+			println(diff.compare_files(opath, vfmt_result_file) or { err.msg() })
 			continue
 		}
 		fmt_bench.ok()
diff --git a/vlib/v/fmt/fmt_vlib_test.v b/vlib/v/fmt/fmt_vlib_test.v
index 341510ed1a..abe657d5ac 100644
--- a/vlib/v/fmt/fmt_vlib_test.v
+++ b/vlib/v/fmt/fmt_vlib_test.v
@@ -50,13 +50,9 @@ fn test_vlib_fmt() {
 		if expected_ocontent != result_ocontent {
 			fmt_bench.fail()
 			eprintln(fmt_bench.step_message_fail('file ${ipath} after formatting, does not look as expected.'))
-			if diff_cmd == '' {
-				eprintln('>> sorry, but no working "diff" CLI command can be found')
-				continue
-			}
-			vfmt_result_file := os.join_path(tmpfolder, 'vfmt_run_over_${ifilename}')
-			os.write_file(vfmt_result_file, result_ocontent) or { panic(err) }
-			eprintln(diff.color_compare_files(diff_cmd, opath, vfmt_result_file))
+			vfmt_result_file := os.join_path(tmpfolder, 'vfmt_run_over_${os.file_name(ipath)}')
+			os.write_file(vfmt_result_file, result_ocontent)!
+			println(diff.compare_files(opath, vfmt_result_file) or { err.msg() })
 			continue
 		}
 		fmt_bench.ok()
diff --git a/vlib/v/gen/c/coutput_test.v b/vlib/v/gen/c/coutput_test.v
index 66edd689c9..f6524b932d 100644
--- a/vlib/v/gen/c/coutput_test.v
+++ b/vlib/v/gen/c/coutput_test.v
@@ -1,5 +1,4 @@
 import os
-import rand
 import time
 import term
 import v.util.diff
@@ -11,8 +10,6 @@ const vroot = os.real_path(@VMODROOT)
 
 const testdata_folder = os.join_path(vroot, 'vlib', 'v', 'gen', 'c', 'testdata')
 
-const diff_cmd = diff.find_working_diff_command() or { '' }
-
 const show_compilation_output = os.getenv('VTEST_SHOW_COMPILATION_OUTPUT').int() == 1
 
 const user_os = os.user_os()
@@ -89,16 +86,16 @@ fn test_out_files() {
 		}
 		if expected != found {
 			println('${term.red('FAIL')} C:${compile_ms:6}ms, R:${run_ms:2}ms ${label}')
-			println(term.header('expected:', '-'))
-			println(expected)
-			println(term.header('found:', '-'))
-			println(found)
-			if diff_cmd != '' {
+			if diff_ := diff.compare_text(expected, found) {
 				println(term.header('difference:', '-'))
-				println(diff.color_compare_strings(diff_cmd, rand.ulid(), expected, found))
+				println(diff_)
 			} else {
-				println(term.h_divider('-'))
+				println(term.header('expected:', '-'))
+				println(expected)
+				println(term.header('found:', '-'))
+				println(found)
 			}
+			println(term.h_divider('-'))
 			total_errors++
 		} else {
 			println('${term.green('OK  ')} C:${compile_ms:6}ms, R:${run_ms:2}ms ${label}')
diff --git a/vlib/v/gen/js/program_test.v b/vlib/v/gen/js/program_test.v
index 26ff6dccc4..b3a0d2619e 100644
--- a/vlib/v/gen/js/program_test.v
+++ b/vlib/v/gen/js/program_test.v
@@ -1,6 +1,5 @@
 import os
 import term
-import rand
 import v.util.vtest
 import v.util.diff
 
@@ -75,14 +74,16 @@ fn check_path(dir string, tests []string) !int {
 		if expected != found {
 			println(term.red('FAIL'))
 			println('============')
-			println('expected ${program_out} content:')
-			println(expected)
-			println('============')
-			println('found:')
-			println(found)
-			println('============\n')
-			println('diff:')
-			println(diff.color_compare_strings(diff_cmd, rand.ulid(), expected, found))
+			if diff_ := diff.compare_text(expected, found) {
+				println('diff:')
+				println(diff_)
+			} else {
+				println('expected ${program_out} content:')
+				println(expected)
+				println('============')
+				println('found:')
+				println(found)
+			}
 			println('============\n')
 			nb_fail++
 		} else {
diff --git a/vlib/v/slow_tests/repl/runner/runner.v b/vlib/v/slow_tests/repl/runner/runner.v
index 6936409fd4..bc20647191 100644
--- a/vlib/v/slow_tests/repl/runner/runner.v
+++ b/vlib/v/slow_tests/repl/runner/runner.v
@@ -34,11 +34,6 @@ pub fn full_path_to_v(dirs_in int) string {
 	return vexec
 }
 
-fn diff_files(file_result string, file_expected string) string {
-	diffcmd := diff.find_working_diff_command() or { return err.msg() }
-	return diff.color_compare_files(diffcmd, file_result, file_expected)
-}
-
 pub fn run_repl_file(wd string, vexec string, file string) !string {
 	vexec_folder := os.dir(vexec) + os.path_separator
 	fcontent := os.read_file(file) or { return error('Could not read repl file ${file}') }
@@ -67,22 +62,9 @@ pub fn run_repl_file(wd string, vexec string, file string) !string {
 	}
 	os.rm(input_temporary_filename)!
 	if result != output {
-		file_result := '${file}.result.txt'
-		file_expected := '${file}.expected.txt'
-		os.write_file(file_result, result) or { panic(err) }
-		os.write_file(file_expected, output) or { panic(err) }
-		diff_ := diff_files(file_expected, file_result)
-		return error('Difference found in REPL file: ${file}
-====> Expected :
-|${output}|
-====> Got      :
-|${result}|
-====> Diff     :
-${diff_}
-		')
-	} else {
-		return file.replace('./', '')
+		return diff_error(file, output, result)
 	}
+	return file.replace('./', '')
 }
 
 pub fn run_prod_file(wd string, vexec string, file string) !string {
@@ -101,20 +83,9 @@ pub fn run_prod_file(wd string, vexec string, file string) !string {
 	}
 	result := r.output.replace('\r', '')
 	if result != expected_content {
-		file_result := '${file}.result.txt'
-		os.write_file(file_result, result) or { panic(err) }
-		diff_ := diff_files(file_result, file_expected)
-		return error('Difference found in test: ${file}
-====> Got      :
-|${result}|
-====> Expected :
-|${expected_content}|
-====> Diff     :
-${diff_}
-		')
-	} else {
-		return 'Prod file ${file} is OK'
+		return diff_error(file, expected_content, result)
 	}
+	return 'Prod file ${file} is OK'
 }
 
 pub fn new_options() RunnerOptions {
@@ -150,3 +121,21 @@ pub fn new_prod_options() RunnerOptions {
 		files: files
 	}
 }
+
+fn diff_error(file string, expected string, found string) IError {
+	header := 'Difference found in REPL file: ${file}'
+	details := if diff_ := diff.compare_text(expected, found) {
+		'
+====> Diff     :
+${diff_}
+'
+	} else {
+		'
+====> Expected :
+|${expected}|
+====> Got      :
+|${found}|
+'
+	}
+	return error(header + details)
+}