diff --git a/.gitignore b/.gitignore
index 0976a34..23f0bd6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,4 @@ example/range
 example/signal
 example/stream1
 example/stream2
+test_runner
diff --git a/Makefile b/Makefile
index 9ac3dcb..3d347d1 100644
--- a/Makefile
+++ b/Makefile
@@ -1,17 +1,23 @@
-EXAMPLES_CXXFLAGS = -O2 -g -std=c++14 -Wall -Wextra -Wshadow -I.
+OSTD_CXXFLAGS = -O2 -g -std=c++14 -Wall -Wextra -Wshadow -I.
 
 EXAMPLES_OBJ = \
-	examples/format.o \
-	examples/listdir.o \
-	examples/range.o \
-	examples/signal.o \
-	examples/stream1.o \
-	examples/stream2.o
+	examples/format \
+	examples/listdir \
+	examples/range \
+	examples/signal \
+	examples/stream1 \
+	examples/stream2
+
+all: examples
 
 examples: $(EXAMPLES_OBJ)
+test_runner: test_runner.o
 
-.cc.o:
-	$(CXX) $(CXXFLAGS) $(EXAMPLES_CXXFLAGS) -o $@ $<
+.cc:
+	$(CXX) $(CXXFLAGS) $(OSTD_CXXFLAGS) -o $@ $<
+
+test: test_runner
+	@./test_runner
 
 clean:
-	rm -f $(EXAMPLES_OBJ)
+	rm -f $(EXAMPLES_OBJ) test_runner
diff --git a/run_tests.py b/run_tests.py
deleted file mode 100644
index 65c6a28..0000000
--- a/run_tests.py
+++ /dev/null
@@ -1,74 +0,0 @@
-from sys import stdout, exit
-from os import listdir, remove, name as osname, getenv
-from os.path import splitext, join as joinp
-import subprocess as sp
-
-# configuration - you can modify this
-
-COMPILER = getenv("CXX", "c++")
-CXXFLAGS = [
-    "-std=c++14",
-    "-Wall", "-Wextra", "-Wshadow",
-    "-Wno-missing-braces", # clang false positive
-    "-I."
-] + getenv("CXXFLAGS", "").split()
-COLORS = (osname != "nt")
-TESTDIR = getenv("TESTDIR", "tests")
-SRCEXT = ".cc"
-
-# don't modify past these lines
-
-nsuccess = 0
-nfailed  = 0
-
-if COLORS:
-    colors = {
-        "red": "\033[91m",
-        "green": "\033[92m",
-        "blue": "\033[94m",
-        "bold": "\033[1m",
-        "end": "\033[0m"
-    }
-else:
-    colors = { "red": "", "green": "", "blue": "", "bold": "", "end": "" }
-
-def print_result(modname, fmsg = None):
-    global nsuccess, nfailed
-    if fmsg:
-        print modname + ("...\t%(red)s%(bold)s(" + fmsg + ")%(end)s") % colors
-        nfailed += 1
-    else:
-        print modname + "...\t%(green)s%(bold)s(success)%(end)s" % colors
-        nsuccess += 1
-
-for fname in listdir(TESTDIR):
-    (modname, modext) = splitext(fname)
-
-    if modext != SRCEXT:
-        continue
-
-    srcpath = joinp(TESTDIR, fname)
-    exepath = joinp(TESTDIR, modname)
-
-    pc = sp.Popen([ COMPILER, srcpath, "-o", exepath ] + CXXFLAGS,
-        stdout = sp.PIPE, stderr = sp.STDOUT)
-    stdout.write(pc.communicate()[0])
-
-    if pc.returncode != 0:
-        print_result(modname, "compile error")
-        continue
-
-    pc = sp.Popen(exepath, stdout = sp.PIPE, stderr = sp.STDOUT)
-    stdout.write(pc.communicate()[0])
-
-    if pc.returncode != 0:
-        remove(exepath)
-        print_result(modname, "runtime error")
-        continue
-
-    remove(exepath)
-    print_result(modname)
-
-print "\n%(blue)s%(bold)stesting done:%(end)s" % colors
-print "%(green)sSUCCESS: " % colors + str(nsuccess) + colors["end"]
-print "%(red)sFAILURE: " % colors + str(nfailed) + colors["end"]
diff --git a/test_runner.cc b/test_runner.cc
new file mode 100644
index 0000000..381851d
--- /dev/null
+++ b/test_runner.cc
@@ -0,0 +1,101 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <ostd/platform.hh>
+#include <ostd/io.hh>
+#include <ostd/string.hh>
+#include <ostd/map.hh>
+#include <ostd/filesystem.hh>
+
+using namespace ostd;
+
+ConstCharRange get_env(ConstCharRange var, ConstCharRange def = nullptr) {
+    const char *ret = getenv(String(var).data());
+    if (!ret || !ret[0])
+        return def;
+    return ret;
+}
+
+int main() {
+    ConstCharRange compiler = get_env("CXX", "c++");
+    ConstCharRange cxxflags = "-std=c++14 -Wall -Wextra -Wshadow "
+                              "-Wno-missing-braces " /* clang false positive */
+                              "-I.";
+    ConstCharRange testdir = get_env("TESTDIR", "tests");
+    ConstCharRange srcext = ".cc";
+
+    Map<ConstCharRange, ConstCharRange> colors = {
+#ifndef OSTD_PLATFORM_WIN32
+        { "red", "\033[91m" },
+        { "green", "\033[92m" },
+        { "blue", "\033[94m" },
+        { "bold", "\033[1m" },
+        { "end", "\033[0m" }
+#else
+        { "red", "" },
+        { "green", "" },
+        { "blue", "" },
+        { "bold", "" },
+        { "end", "" }
+#endif
+    };
+
+    String cxxf = cxxflags;
+    cxxf += get_env("CXXFLAGS", "");
+
+    int nsuccess = 0, nfailed = 0;
+
+    auto print_result = [&colors, &nsuccess, &nfailed]
+                        (ConstCharRange modname, ConstCharRange fmsg = nullptr) {
+        if (!fmsg.empty()) {
+            writeln(modname, "...\t", colors["red"], colors["bold"],
+                    "(", fmsg, ")", colors["end"]);
+            ++nfailed;
+        } else {
+            writeln(modname, "...\t", colors["green"], colors["bold"],
+                    "(success)", colors["end"]);
+            ++nsuccess;
+        }
+    };
+
+    DirectoryStream ds(testdir);
+    for (auto v: ds.iter()) {
+        if (v.type() != FileType::regular)
+            continue;
+        if (v.extension() != srcext)
+            continue;
+
+        String exepath = testdir;
+        exepath += PathSeparator;
+        exepath += v.stem();
+
+        String cxxcmd = compiler;
+        cxxcmd += " ";
+        cxxcmd += testdir;
+        cxxcmd += PathSeparator;
+        cxxcmd += v.filename();
+        cxxcmd += " -o ";
+        cxxcmd += exepath;
+        cxxcmd += " ";
+        cxxcmd += cxxf;
+
+        int ret = system(cxxcmd.data());
+        if (ret) {
+            print_result(v.stem(), "compile errror");
+            continue;
+        }
+
+        ret = system(exepath.data());
+        if (ret) {
+            print_result(v.stem(), "runtime error");
+            continue;
+        }
+
+        remove(exepath.data());
+        print_result(v.stem());
+    }
+
+    writeln("\n", colors["blue"], colors["bold"], "testing done:", colors["end"]);
+    writeln(colors["green"], "SUCCESS: ", nsuccess, colors["end"]);
+    writeln(colors["red"], "FAILURE: ", nfailed, colors["end"]);
+}