diff --git a/doc/grammar.bnf b/doc/grammar.bnf
index 699445f..8754905 100644
--- a/doc/grammar.bnf
+++ b/doc/grammar.bnf
@@ -1,5 +1,9 @@
-PROG ::= (INSTR (EOI INSTR)*)?
+PROG ::= (INSTR (EOI+ INSTR)*)?
+
 INSTR ::= EXPR
+| assert EXPR
+| assert_static_fail EXPR
+
 EXPR ::= IMP
 
 IMP ::= OR (imp OR)?
diff --git a/lib/Compiler.cpp b/lib/Compiler.cpp
index 43a8f5f..02f8fc0 100644
--- a/lib/Compiler.cpp
+++ b/lib/Compiler.cpp
@@ -1,5 +1,7 @@
 #include "Compiler.hpp"
+#include "lib/Node.hpp"
 #include "lib/opcodes.hpp"
+#include "StaticPass.hpp"
 
 namespace roza
 {
@@ -23,6 +25,33 @@ namespace roza
   {
     switch (root->type())
       {
+      case NODE_ASSERT: {
+        compile_children(root, prog);
+        prog->push_instr(OP_ASSERT);
+      } break;
+
+      case NODE_ASSERT_STATIC_FAIL: {
+        bool failed = false;
+
+        try
+          {
+            StaticPass static_pass {m_log};
+            static_pass.check_children(root);
+            compile_children(root, prog);
+
+            failed = true;
+          }
+        catch(...)
+          {
+          }
+
+        if (failed)
+          {
+            m_log.fatal(root->loc(), "static assertion failed");
+          }
+
+      } break;
+
       case NODE_INT: {
         auto value = std::make_shared<Value>(std::stoi(root->repr()), root->loc());
         prog->push_instr(OP_PUSH_CONST, prog->push_value(value));
diff --git a/lib/Lexer.cpp b/lib/Lexer.cpp
index b21ebbf..b0fbf73 100644
--- a/lib/Lexer.cpp
+++ b/lib/Lexer.cpp
@@ -31,6 +31,8 @@ namespace roza
       {"and", NODE_AND, false},
       {"or", NODE_OR, false},
       {"not", NODE_NOT, false},
+      {"assert_static_fail", NODE_ASSERT_STATIC_FAIL, false},
+      {"assert", NODE_ASSERT, false},
     };
 
 
diff --git a/lib/Node.hpp b/lib/Node.hpp
index 6026ba1..35657ab 100644
--- a/lib/Node.hpp
+++ b/lib/Node.hpp
@@ -9,9 +9,9 @@
     G(NODE_INT), G(NODE_ADD), G(NODE_SUB), G(NODE_MUL),         \
     G(NODE_DIV), G(NODE_MOD), G(NODE_POW), G(NODE_OPAR),        \
     G(NODE_CPAR), G(NODE_UADD), G(NODE_USUB), G(NODE_BOOL),     \
-    G(NODE_AND), G(NODE_OR), G(NODE_NOT), G(NODE_IMP), \
+    G(NODE_AND), G(NODE_OR), G(NODE_NOT), G(NODE_IMP),          \
     G(NODE_EQ), G(NODE_NE), G(NODE_LT), G(NODE_LE), G(NODE_GT), \
-    G(NODE_GE)
+    G(NODE_GE), G(NODE_ASSERT), G(NODE_ASSERT_STATIC_FAIL)
 
 namespace roza
 {
diff --git a/lib/Parser.cpp b/lib/Parser.cpp
index 43165e5..953e3f9 100644
--- a/lib/Parser.cpp
+++ b/lib/Parser.cpp
@@ -1,5 +1,6 @@
 #include "Parser.hpp"
 #include "lib/Node.hpp"
+#include <memory>
 
 namespace roza
 {
@@ -67,6 +68,7 @@ namespace roza
                     + "', got '"
                     + NodeTypeStr[type()]
                     + "'");
+
         return nullptr;
       }
 
@@ -118,7 +120,21 @@ namespace roza
   std::shared_ptr<Node> Parser::parse_instr()
   {
     consume_all(NODE_EOI);
-    auto root = parse_expr();
+
+    std::shared_ptr<Node> root;
+
+    if (type_is(NODE_ASSERT)
+        || type_is(NODE_ASSERT_STATIC_FAIL))
+      {
+        root = consume();
+        root->add_child(parse_expr());
+      }
+    else
+      {
+        root = parse_expr();
+      }
+
+
     consume_or_nullptr(NODE_EOI);
     consume_all(NODE_EOI);
 
diff --git a/lib/StaticPass.cpp b/lib/StaticPass.cpp
index a38c702..2e11121 100644
--- a/lib/StaticPass.cpp
+++ b/lib/StaticPass.cpp
@@ -19,6 +19,7 @@ namespace roza
 
     switch (root->type())
       {
+      case NODE_ASSERT_STATIC_FAIL:
       case NODE_INT:
       case NODE_BOOL:
         break;
@@ -41,6 +42,7 @@ namespace roza
         check_types(root, lhs, rhs);
       } break;
 
+      case NODE_ASSERT:
       case NODE_NOT: {
         check_children(root);
         auto lhs = resolver.find(root->child(0));
@@ -67,6 +69,8 @@ namespace roza
       case NODE_UADD:
       case NODE_USUB: {
         check_children(root);
+        auto lhs = resolver.find(root->child(0));
+        check_types(root, lhs, std::make_shared<Type>(TY_INT));
       } break;
 
       case NODE_PROG: {
diff --git a/lib/VM.cpp b/lib/VM.cpp
index a5de8a9..103df2b 100644
--- a/lib/VM.cpp
+++ b/lib/VM.cpp
@@ -19,6 +19,18 @@ namespace roza
       {
         switch (program->opcode(m_pc))
           {
+          case OP_ASSERT: {
+            auto value = program->value(pop());
+
+            if (!value->as_bool())
+              {
+                m_log.fatal(value->loc(), "assertion failed");
+              }
+
+            m_pc++;
+
+          } break;
+
           case OP_PUSH_CONST: {
             param_t param = *program->param(m_pc);
             push(param);
diff --git a/lib/opcodes.hpp b/lib/opcodes.hpp
index 6efdc66..055339c 100644
--- a/lib/opcodes.hpp
+++ b/lib/opcodes.hpp
@@ -8,7 +8,7 @@
     G(OP_POP), \
     G(OP_IADD), G(OP_ISUB), G(OP_IMUL), G(OP_IDIV), G(OP_IMOD), G(OP_IPOW), \
     G(OP_MOD), G(OP_IUADD), G(OP_IUSUB), G(OP_AND), G(OP_OR), G(OP_NOT), \
-    G(OP_IMP), G(OP_EQ), G(OP_ILT), G(OP_IGT)
+    G(OP_IMP), G(OP_EQ), G(OP_ILT), G(OP_IGT), G(OP_ASSERT)
 
 namespace roza
 {
diff --git a/roza_tests/run.sh b/roza_tests/run.sh
new file mode 100755
index 0000000..e3dca5b
--- /dev/null
+++ b/roza_tests/run.sh
@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+
+OK=0
+KO=0
+TOTAL=0
+
+for file in $(find . -name "test_*.roza" | sort)
+do
+    roza $file
+    RET="$?"
+    NAME=$(basename "$file" | cut -d '.' -f1)
+
+    echo -en "\e[34m$NAME...\e[0m"
+
+    if [ "$RET" == 0 ]
+    then
+        echo -e " \e[32mok\e[0m"
+        OK=$(($OK + 1))
+    else
+        echo -e " \e[31mko\e[0m"
+        KO=$(($KO + 1))
+    fi
+
+    TOTAL=$(($TOTAL + 1))
+done
+
+if [ $OK -eq $TOTAL ]
+then
+    echo -e "\e[32m=== all tests passed ($OK) ===\e[0m"
+    exit 0
+else
+    echo -e "\e[31m=== some tests failed ($KO) ===\e[0m"
+    exit -1
+fi
diff --git a/roza_tests/test_bool.roza b/roza_tests/test_bool.roza
new file mode 100644
index 0000000..36d5783
--- /dev/null
+++ b/roza_tests/test_bool.roza
@@ -0,0 +1,30 @@
+assert true == true
+assert false == false
+
+assert true == (true and true)
+assert false == (true and false)
+assert false == (false and true)
+assert false == (false and false)
+
+assert true == (true or true)
+assert true == (true or false)
+assert true == (false or true)
+assert false == (false or false)
+
+assert false == not true
+assert true == not false
+
+assert true == (true => true)
+assert false == (true => false)
+assert true == (false => true)
+assert true == (false => false)
+
+assert (false or true) == (not (true and false))
+
+assert_static_fail 1 and true
+assert_static_fail false and 7
+assert_static_fail 1 or true
+assert_static_fail false or 7
+assert_static_fail not 9
+assert_static_fail 3 => true
+assert_static_fail true => 7
diff --git a/roza_tests/test_int.roza b/roza_tests/test_int.roza
new file mode 100644
index 0000000..4d50a09
--- /dev/null
+++ b/roza_tests/test_int.roza
@@ -0,0 +1,54 @@
+assert 5 == 5
+assert 3 != 5
+assert -9 == -10 + 1
+assert -4 == 3 - 7
+assert 4 == 7 - 3
+assert 21 == 3 * 7
+assert 3 == 21 / 7
+assert 2 == 21 / 8
+assert 3 == 7 % 4
+assert 128 == 2 ^ 7
+assert -128 == -2 ^ 7
+assert 3 == +3
+assert 0 - 7 == -7
+
+assert 7 == 1 + 2 * 3
+assert 9 == (1 + 2) * 3
+
+assert true == 5 < 6
+assert false == 5 < 5
+assert false == 5 < 4
+assert true == 5 <= 6
+assert true == 5 <= 5
+assert false == 5 <= 4
+assert false == 5 > 6
+assert false == 5 > 5
+assert true == 5 > 4
+assert false == 5 >= 6
+assert true == 5 >= 5
+assert true == 5 >= 4
+
+assert_static_fail 5 + true
+assert_static_fail 5 - true
+assert_static_fail 5 * true
+assert_static_fail 5 / true
+assert_static_fail 5 % true
+assert_static_fail 5 ^ true
+assert_static_fail -true
+assert_static_fail +true
+
+assert_static_fail true + 9
+assert_static_fail true - (4 + 1)
+assert_static_fail true * 7
+assert_static_fail true / 3
+assert_static_fail true % 15
+assert_static_fail true ^ 2
+
+assert_static_fail true > 1
+assert_static_fail 2 > false
+assert_static_fail true < 1
+assert_static_fail 2 < false
+assert_static_fail true >= 1
+assert_static_fail 2 >= false
+assert_static_fail true <= 1
+assert_static_fail 2 <= false
diff --git a/src/main.cpp b/src/main.cpp
index 9fa81de..89ba862 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -33,51 +33,61 @@ int main(int argc, char** argv)
 
   if (args.inputs().size() > 0)
     {
-      auto source = loader.load(args.inputs()[0]);
-      roza::SrcLoc loc {args.inputs()[0]};
-      roza::StatusLog log;
-
-      auto lexer = std::make_shared<roza::Lexer>(log, loc);
-      auto parser = std::make_shared<roza::Parser>(*lexer, log);
-      auto static_pass = std::make_shared<roza::StaticPass>(log);
-      auto compiler = std::make_shared<roza::Compiler>(log);
-      auto vm = std::make_shared<roza::VM>(log);
-
-      lexer->scan(source);
-
-      if (args.get("--tokens"))
+      try
         {
-          std::cout << "Tokens:" << std::endl;
-          for (size_t i=0; i<lexer->size(); i++)
+          auto source = loader.load(args.inputs()[0]);
+          roza::SrcLoc loc {args.inputs()[0]};
+          roza::StatusLog log;
+
+          auto lexer = std::make_shared<roza::Lexer>(log, loc);
+          auto parser = std::make_shared<roza::Parser>(*lexer, log);
+          auto static_pass = std::make_shared<roza::StaticPass>(log);
+          auto compiler = std::make_shared<roza::Compiler>(log);
+          auto vm = std::make_shared<roza::VM>(log);
+
+          lexer->scan(source);
+
+          if (args.get("--tokens"))
             {
-              std::cout << "\t" << lexer->get_or_nullptr(i)->string() << std::endl;
+              std::cout << "Tokens:" << std::endl;
+              for (size_t i=0; i<lexer->size(); i++)
+                {
+                  std::cout << "\t" << lexer->get_or_nullptr(i)->string() << std::endl;
+                }
             }
+
+          auto root = parser->parse();
+
+          if (args.get("--ast"))
+            {
+              std::cout << "AST:" << std::endl;
+              std::cout << root->string() << std::endl;
+            }
+
+          static_pass->check(root);
+          auto prog = compiler->compile(root);
+
+          if (args.get("--code"))
+            {
+              std::cout << "Bytecode:" << std::endl;
+              std::cout << prog->string() << std::endl;
+            }
+
+          vm->exec(prog);
+
+          if (args.get("--stack"))
+            {
+              std::cout << vm->string() << std::endl;
+            }
+
+          return 0;
         }
-
-      auto root = parser->parse();
-
-      if (args.get("--ast"))
+      catch(std::exception const& err)
         {
-          std::cout << "AST:" << std::endl;
-          std::cout << root->string() << std::endl;
+          std::cerr << err.what() << std::endl;
+          return -1;
         }
 
-      static_pass->check(root);
-      auto prog = compiler->compile(root);
-
-      if (args.get("--code"))
-        {
-          std::cout << "Bytecode:" << std::endl;
-          std::cout << prog->string() << std::endl;
-        }
-
-      vm->exec(prog);
-
-      if (args.get("--stack"))
-        {
-          std::cout << vm->string() << std::endl;
-        }
+      return 0;
     }
-
-  return 0;
 }
diff --git a/tests/Lexer.cpp b/tests/Lexer.cpp
index 33e2a8c..72047be 100644
--- a/tests/Lexer.cpp
+++ b/tests/Lexer.cpp
@@ -65,30 +65,32 @@ TEST_CASE_METHOD(LexerTest, "Lexer_keywords")
 
 TEST_CASE_METHOD(LexerTest, "Lexer_bool")
 {
-  SECTION("nominal cases")
-    {
-      m_lexer.scan("and or not true false =>");
-      REQUIRE("AND" == get_str(0));
-      REQUIRE("OR" == get_str(1));
-      REQUIRE("NOT" == get_str(2));
-      REQUIRE("BOOL[true]" == get_str(3));
-      REQUIRE("BOOL[false]" == get_str(4));
-      REQUIRE("IMP" == get_str(5));
-      REQUIRE("" == get_str(6));
-    }
+  m_lexer.scan("and or not true false =>");
+  REQUIRE("AND" == get_str(0));
+  REQUIRE("OR" == get_str(1));
+  REQUIRE("NOT" == get_str(2));
+  REQUIRE("BOOL[true]" == get_str(3));
+  REQUIRE("BOOL[false]" == get_str(4));
+  REQUIRE("IMP" == get_str(5));
+  REQUIRE("" == get_str(6));
 }
 
 TEST_CASE_METHOD(LexerTest, "Lexer_comparisons")
 {
-  SECTION("nominal cases")
-    {
-      m_lexer.scan("== != < > <= >=");
-      REQUIRE("EQ" == get_str(0));
-      REQUIRE("NE" == get_str(1));
-      REQUIRE("LT" == get_str(2));
-      REQUIRE("GT" == get_str(3));
-      REQUIRE("LE" == get_str(4));
-      REQUIRE("GE" == get_str(5));
-      REQUIRE("" == get_str(6));
-    }
+  m_lexer.scan("== != < > <= >=");
+  REQUIRE("EQ" == get_str(0));
+  REQUIRE("NE" == get_str(1));
+  REQUIRE("LT" == get_str(2));
+  REQUIRE("GT" == get_str(3));
+  REQUIRE("LE" == get_str(4));
+  REQUIRE("GE" == get_str(5));
+  REQUIRE("" == get_str(6));
+}
+
+TEST_CASE_METHOD(LexerTest, "Lexer_asserts")
+{
+  m_lexer.scan(" assert assert_static_fail ");
+  REQUIRE("ASSERT" == get_str(0));
+  REQUIRE("ASSERT_STATIC_FAIL" == get_str(1));
+  REQUIRE("" == get_str(2));
 }
diff --git a/tests/Parser.cpp b/tests/Parser.cpp
index 3e59547..03b2819 100644
--- a/tests/Parser.cpp
+++ b/tests/Parser.cpp
@@ -100,3 +100,13 @@ TEST_CASE_METHOD(ParserTest, "Parser_comparisons")
   test_node("PROG(EQ(LE(INT[5],INT[3]),BOOL[false]))",
             "5 <= 3 == false");
 }
+
+
+TEST_CASE_METHOD(ParserTest, "Parser_assertions")
+{
+  test_node("PROG(ASSERT(EQ(ADD(INT[1],INT[1]),INT[2])))",
+            "assert 1 + 1 == 2");
+
+  test_node("PROG(ASSERT_STATIC_FAIL(EQ(ADD(INT[1],INT[1]),INT[2])))",
+            "assert_static_fail 1 + 1 == 2");
+}