diff --git a/octa/array.h b/octa/array.h
index 8882ac7..7da91ad 100644
--- a/octa/array.h
+++ b/octa/array.h
@@ -42,7 +42,7 @@ namespace octa {
         bool empty() const { return N == 0; }
 
         bool in_range(size_t idx) { return idx < N; }
-        bool in_range(int idx) { return idx >= 0 && idx < N; }
+        bool in_range(int idx) { return idx >= 0 && size_t(idx) < N; }
         bool in_range(const T *ptr) {
             return ptr >= &p_buf[0] && ptr < &p_buf[N];
         }
diff --git a/octa/vector.h b/octa/vector.h
index 34e0485..5b9de80 100644
--- a/octa/vector.h
+++ b/octa/vector.h
@@ -251,7 +251,7 @@ namespace octa {
         bool empty() const { return (p_len == 0); }
 
         bool in_range(size_t idx) { return idx < p_len; }
-        bool in_range(int idx) { return idx >= 0 && idx < p_len; }
+        bool in_range(int idx) { return idx >= 0 && size_t(idx) < p_len; }
         bool in_range(const T *ptr) {
             return ptr >= p_buf && ptr < &p_buf[p_len];
         }
diff --git a/run_tests.py b/run_tests.py
index 81c0805..fb0f9af 100644
--- a/run_tests.py
+++ b/run_tests.py
@@ -4,29 +4,34 @@ from os.path import splitext
 import subprocess as sp
 
 COMPILER = "c++"
-CXXFLAGS="-std=c++11 -Wall -Wextra -I."
+# -Wno-missing-braces because clang false positive
+CXXFLAGS="-std=c++11 -Wall -Wextra -Wno-missing-braces -I."
 
 for fname in listdir("./tests"):
-    if fname.endswith(".cpp"):
-        modname = splitext(fname)[0]
-        stdout.write("%s...\t" % modname)
-        pc = sp.Popen("%s tests/%s -o tests/%s %s"
-            % (COMPILER, fname, modname, CXXFLAGS), shell = True,
-                stdout = sp.PIPE, stderr = sp.STDOUT)
-        pcdata = pc.communicate()[0]
-        if pc.returncode != 0:
-            print "\033[91m(compile error)\033[0m"
-            stdout.write(pcdata)
-            exit(1)
-        pc = sp.Popen("./tests/%s" % modname, shell = True,
-            stdout = sp.PIPE, stderr = sp.STDOUT)
-        pcdata = pc.communicate()[0]
-        if pc.returncode != 0:
-            remove("./tests/%s" % modname)
-            print "\033[91m(runtime error)\033[0m"
-            stdout.write(pcdata)
-            exit(1)
-        remove("./tests/%s" % modname)
-        print "\033[92m(success)\033[0m"
+    (modname, modext) = splitext(fname)
 
-print "testing successful"
\ No newline at end of file
+    if modext != ".cpp":
+        continue
+
+    pc = sp.Popen("%s tests/%s -o tests/%s %s"
+        % (COMPILER, fname, modname, CXXFLAGS), shell = True,
+            stdout = sp.PIPE, stderr = sp.STDOUT)
+    stdout.write(pc.communicate()[0])
+
+    if pc.returncode != 0:
+        print "%s...\t\033[91m\033[1m(compile error)\033[0m" % modname
+        exit(1)
+
+    pc = sp.Popen("./tests/%s" % modname, shell = True,
+        stdout = sp.PIPE, stderr = sp.STDOUT)
+    stdout.write(pc.communicate()[0])
+
+    if pc.returncode != 0:
+        remove("./tests/%s" % modname)
+        print "%s...\t\033[91m\033[1m(runtime error)\033[0m" % modname
+        exit(1)
+
+    remove("./tests/%s" % modname)
+    print "%s...\t\033[92m\033[1m(success)\033[0m" % modname
+
+print "\033[94m\033[1mtesting successful\033[0m"
\ No newline at end of file
diff --git a/tests/array.cpp b/tests/array.cpp
index ee74bcb..d1b99cf 100644
--- a/tests/array.cpp
+++ b/tests/array.cpp
@@ -1,5 +1,45 @@
+#include <assert.h>
+#include <string.h>
 #include "octa/array.h"
+#include "octa/string.h"
+
+using namespace octa;
 
 int main() {
+    Array<int, 5> x = { 2, 4, 8, 16, 32 };
+
+    assert(x.first() == 2);
+    assert(x.last() == 32);
+
+    assert(x[0] == 2);
+    assert(x[2] == 8);
+
+    assert(x.at(0) == x[0]);
+    assert(x.at(3) == x[3]);
+
+    assert(x.size() == 5);
+
+    assert(!x.empty());
+
+    assert(x.in_range(4));
+    assert(x.in_range(0));
+    assert(!x.in_range(5));
+
+    assert(x.data()[0] == x[0]);
+
+    auto r = x.each();
+    assert(r.first() == 2);
+    assert(r.last() == 32);
+
+    Array<int, 5> z;
+    x.swap(z);
+
+    assert(z.first() == 2);
+    assert(z.last() == 32);
+
+    assert(z.size() == 5);
+
+    assert(!strcmp(to_string(z).data(), "{2, 4, 8, 16, 32}"));
+
     return 0;
 }
\ No newline at end of file
diff --git a/tests/vector.cpp b/tests/vector.cpp
index 6f5d65a..752a915 100644
--- a/tests/vector.cpp
+++ b/tests/vector.cpp
@@ -1,5 +1,7 @@
 #include <assert.h>
+#include <string.h>
 #include "octa/vector.h"
+#include "octa/string.h"
 
 using namespace octa;
 
@@ -12,6 +14,11 @@ int main() {
     assert(x[0] == 5);
     assert(x[2] == 15);
 
+    assert(x.at(0) == x[0]);
+    assert(x.at(3) == x[3]);
+
+    assert(x.data()[0] == x[0]);
+
     assert(x.size() == 4);
 
     Vector<int> y(5, 10);
@@ -78,5 +85,7 @@ int main() {
     assert(w.first() == 5);
     assert(w.last() == 5);
 
+    assert(!strcmp(to_string(w).data(), "{5, 5, 4, 5, 5, 5, 5, 5, 5, 5, 5}"));
+
     return 0;
 }
\ No newline at end of file