diff --git a/src/bin/expect_tests/dune b/src/bin/expect_tests/dune
index 65504a168..099f8a7b7 100644
--- a/src/bin/expect_tests/dune
+++ b/src/bin/expect_tests/dune
@@ -1,6 +1,6 @@
 (library
  (name cli_expect_tests)
  (libraries simple-utils cli)
- (inline_tests (deps (source_tree ../../test/contracts)))
+ (inline_tests (deps (source_tree ../../test/contracts) (source_tree ../../test/lexer)))
  (preprocess (pps ppx_let ppx_expect))
  (flags (:standard -open Simple_utils)))
diff --git a/src/bin/expect_tests/lexer_tests.ml b/src/bin/expect_tests/lexer_tests.ml
new file mode 100644
index 000000000..06188eba2
--- /dev/null
+++ b/src/bin/expect_tests/lexer_tests.ml
@@ -0,0 +1,153 @@
+open Cli_expect
+
+let%expect_test _ =
+    run_ligo_bad [ "compile-contract" ; "../../test/lexer/broken_string.ligo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: The string starting here is interrupted by a line break.
+      Hint: Remove the break, close the string before or insert a backslash.
+       {"parser_loc":"in file \"broken_string.ligo\", line 1, characters 18-19"}      
+ |} ];
+
+    run_ligo_bad [ "compile-contract" ; "../../test/lexer/broken_string.mligo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: The string starting here is interrupted by a line break.
+      Hint: Remove the break, close the string before or insert a backslash.
+       {"parser_loc":"in file \"broken_string.mligo\", line 1, characters 8-9"}      
+ |} ];
+
+ run_ligo_bad [ "compile-contract" ; "../../test/lexer/broken_string.religo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: The string starting here is interrupted by a line break.
+      Hint: Remove the break, close the string before or insert a backslash.
+       {"parser_loc":"in file \"broken_string.religo\", line 1, characters 8-9"}
+ |} ];
+
+run_ligo_bad [ "compile-contract" ; "../../test/lexer/negative_byte_sequence.ligo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Negative byte sequence.
+      Hint: Remove the leading minus sign.
+       {"parser_loc":"in file \"negative_byte_sequence.ligo\", line 1, characters 18-23"}
+ |} ];
+
+run_ligo_bad [ "compile-contract" ; "../../test/lexer/negative_byte_sequence.mligo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Negative byte sequence.
+      Hint: Remove the leading minus sign.
+       {"parser_loc":"in file \"negative_byte_sequence.mligo\", line 1, characters 8-13"}
+ |} ];
+
+run_ligo_bad [ "compile-contract" ; "../../test/lexer/negative_byte_sequence.religo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Negative byte sequence.
+      Hint: Remove the leading minus sign.
+       {"parser_loc":"in file \"negative_byte_sequence.religo\", line 1, characters 8-13"}            
+ |} ];
+
+ run_ligo_bad [ "compile-contract" ; "../../test/lexer/reserved_name.ligo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Reserved name: args.
+      Hint: Change the name.
+       {"parser_loc":"in file \"reserved_name.ligo\", line 1, characters 4-8"}
+ |} ];
+
+run_ligo_bad [ "compile-contract" ; "../../test/lexer/reserved_name.religo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Reserved name: end.
+      Hint: Change the name.
+       {"parser_loc":"in file \"reserved_name.religo\", line 1, characters 4-7"}
+ |} ];
+
+run_ligo_bad [ "compile-contract" ; "../../test/lexer/reserved_name.mligo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Reserved name: object.
+      Hint: Change the name.
+       {"parser_loc":"in file \"reserved_name.mligo\", line 1, characters 4-10"}
+ |} ];
+
+run_ligo_bad [ "compile-contract" ; "../../test/lexer/unexpected_character.ligo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Unexpected character '\239'.
+       {"parser_loc":"in file \"unexpected_character.ligo\", line 1, characters 18-19"}
+ |} ];
+
+ run_ligo_bad [ "compile-contract" ; "../../test/lexer/unexpected_character.mligo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Unexpected character '\239'.
+       {"parser_loc":"in file \"unexpected_character.mligo\", line 1, characters 8-9"}
+ |} ];
+
+ run_ligo_bad [ "compile-contract" ; "../../test/lexer/unexpected_character.religo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Unexpected character '\239'.
+       {"parser_loc":"in file \"unexpected_character.religo\", line 1, characters 8-9"}
+ |} ];
+
+ run_ligo_bad [ "compile-contract" ; "../../test/lexer/unterminated_comment.mligo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Unterminated comment.
+      Hint: Close with "*)".
+       {"parser_loc":"in file \"unterminated_comment.mligo\", line 1, characters 0-2"}
+ |} ];
+
+run_ligo_bad [ "compile-contract" ; "../../test/lexer/invalid_symbol.ligo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Invalid symbol.
+      Hint: Check the LIGO syntax you use.
+       {"parser_loc":"in file \"invalid_symbol.ligo\", line 1, characters 17-20"}
+ |} ];
+
+run_ligo_bad [ "compile-contract" ; "../../test/lexer/invalid_symbol.mligo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Invalid symbol.
+      Hint: Check the LIGO syntax you use.
+       {"parser_loc":"in file \"invalid_symbol.mligo\", line 1, characters 10-13"}
+ |} ];
+
+run_ligo_bad [ "compile-contract" ; "../../test/lexer/invalid_symbol.religo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Invalid symbol.
+      Hint: Check the LIGO syntax you use.
+       {"parser_loc":"in file \"invalid_symbol.religo\", line 1, characters 10-11"}
+ |} ];
+
+ run_ligo_bad [ "compile-contract" ; "../../test/lexer/missing_break.ligo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Missing break.
+      Hint: Insert some space.
+       {"parser_loc":"in file \"missing_break.ligo\", line 1, characters 18-18"}
+ |} ];
+
+ run_ligo_bad [ "compile-contract" ; "../../test/lexer/missing_break.mligo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Missing break.
+      Hint: Insert some space.
+       {"parser_loc":"in file \"missing_break.mligo\", line 1, characters 11-11"}
+ |} ];
+
+ run_ligo_bad [ "compile-contract" ; "../../test/lexer/missing_break.religo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Missing break.
+      Hint: Insert some space.
+       {"parser_loc":"in file \"missing_break.religo\", line 1, characters 11-11"}
+ |} ];
+
+run_ligo_bad [ "compile-contract" ; "../../test/lexer/invalid_character_in_string.ligo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Invalid character in string.
+      Hint: Remove or replace the character.
+       {"parser_loc":"in file \"invalid_character_in_string.ligo\", line 1, characters 19-20"}
+ |} ];
+
+run_ligo_bad [ "compile-contract" ; "../../test/lexer/invalid_character_in_string.mligo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Invalid character in string.
+      Hint: Remove or replace the character.
+       {"parser_loc":"in file \"invalid_character_in_string.mligo\", line 1, characters 9-10"}
+ |} ];
+
+run_ligo_bad [ "compile-contract" ; "../../test/lexer/invalid_character_in_string.religo" ; "main" ] ;
+  [%expect {| 
+ligo: lexer error: Invalid character in string.
+      Hint: Remove or replace the character.
+       {"parser_loc":"in file \"invalid_character_in_string.religo\", line 1, characters 9-10"}
+ |} ]
\ No newline at end of file
diff --git a/src/test/lexer/broken_string.ligo b/src/test/lexer/broken_string.ligo
new file mode 100644
index 000000000..870fe9481
--- /dev/null
+++ b/src/test/lexer/broken_string.ligo
@@ -0,0 +1,4 @@
+const a: string = "broken
+over 
+multiple
+lines";
\ No newline at end of file
diff --git a/src/test/lexer/broken_string.mligo b/src/test/lexer/broken_string.mligo
new file mode 100644
index 000000000..0e9b58689
--- /dev/null
+++ b/src/test/lexer/broken_string.mligo
@@ -0,0 +1,4 @@
+let a = "broken
+over 
+multiple
+lines";
\ No newline at end of file
diff --git a/src/test/lexer/broken_string.religo b/src/test/lexer/broken_string.religo
new file mode 100644
index 000000000..0e9b58689
--- /dev/null
+++ b/src/test/lexer/broken_string.religo
@@ -0,0 +1,4 @@
+let a = "broken
+over 
+multiple
+lines";
\ No newline at end of file
diff --git a/src/test/lexer/invalid_character_in_string.ligo b/src/test/lexer/invalid_character_in_string.ligo
new file mode 100644
index 000000000..48f7167d1
--- /dev/null
+++ b/src/test/lexer/invalid_character_in_string.ligo
@@ -0,0 +1 @@
+const z: string = "	";
\ No newline at end of file
diff --git a/src/test/lexer/invalid_character_in_string.mligo b/src/test/lexer/invalid_character_in_string.mligo
new file mode 100644
index 000000000..f80aa6504
--- /dev/null
+++ b/src/test/lexer/invalid_character_in_string.mligo
@@ -0,0 +1 @@
+let z = "	";
\ No newline at end of file
diff --git a/src/test/lexer/invalid_character_in_string.religo b/src/test/lexer/invalid_character_in_string.religo
new file mode 100644
index 000000000..f80aa6504
--- /dev/null
+++ b/src/test/lexer/invalid_character_in_string.religo
@@ -0,0 +1 @@
+let z = "	";
\ No newline at end of file
diff --git a/src/test/lexer/invalid_symbol.ligo b/src/test/lexer/invalid_symbol.ligo
new file mode 100644
index 000000000..77f5d0984
--- /dev/null
+++ b/src/test/lexer/invalid_symbol.ligo
@@ -0,0 +1 @@
+const b: int = 1 ... 10;
\ No newline at end of file
diff --git a/src/test/lexer/invalid_symbol.mligo b/src/test/lexer/invalid_symbol.mligo
new file mode 100644
index 000000000..91a1290ea
--- /dev/null
+++ b/src/test/lexer/invalid_symbol.mligo
@@ -0,0 +1 @@
+let b = 1 ... 10;
\ No newline at end of file
diff --git a/src/test/lexer/invalid_symbol.religo b/src/test/lexer/invalid_symbol.religo
new file mode 100644
index 000000000..246855122
--- /dev/null
+++ b/src/test/lexer/invalid_symbol.religo
@@ -0,0 +1 @@
+let b = 1 # 10;
\ No newline at end of file
diff --git a/src/test/lexer/missing_break.ligo b/src/test/lexer/missing_break.ligo
new file mode 100644
index 000000000..48d580b70
--- /dev/null
+++ b/src/test/lexer/missing_break.ligo
@@ -0,0 +1 @@
+const a: int = 300zennies;
\ No newline at end of file
diff --git a/src/test/lexer/missing_break.mligo b/src/test/lexer/missing_break.mligo
new file mode 100644
index 000000000..6a2b62143
--- /dev/null
+++ b/src/test/lexer/missing_break.mligo
@@ -0,0 +1 @@
+let a = 300zennies;
\ No newline at end of file
diff --git a/src/test/lexer/missing_break.religo b/src/test/lexer/missing_break.religo
new file mode 100644
index 000000000..6a2b62143
--- /dev/null
+++ b/src/test/lexer/missing_break.religo
@@ -0,0 +1 @@
+let a = 300zennies;
\ No newline at end of file
diff --git a/src/test/lexer/negative_byte_sequence.ligo b/src/test/lexer/negative_byte_sequence.ligo
new file mode 100644
index 000000000..b70da4d24
--- /dev/null
+++ b/src/test/lexer/negative_byte_sequence.ligo
@@ -0,0 +1 @@
+const a: string = -0x222;
\ No newline at end of file
diff --git a/src/test/lexer/negative_byte_sequence.mligo b/src/test/lexer/negative_byte_sequence.mligo
new file mode 100644
index 000000000..2494567f4
--- /dev/null
+++ b/src/test/lexer/negative_byte_sequence.mligo
@@ -0,0 +1 @@
+let a = -0x222;
\ No newline at end of file
diff --git a/src/test/lexer/negative_byte_sequence.religo b/src/test/lexer/negative_byte_sequence.religo
new file mode 100644
index 000000000..2494567f4
--- /dev/null
+++ b/src/test/lexer/negative_byte_sequence.religo
@@ -0,0 +1 @@
+let a = -0x222;
\ No newline at end of file
diff --git a/src/test/lexer/reserved_name.ligo b/src/test/lexer/reserved_name.ligo
new file mode 100644
index 000000000..dfa90cb08
--- /dev/null
+++ b/src/test/lexer/reserved_name.ligo
@@ -0,0 +1 @@
+let args = 1;
\ No newline at end of file
diff --git a/src/test/lexer/reserved_name.mligo b/src/test/lexer/reserved_name.mligo
new file mode 100644
index 000000000..c053ff506
--- /dev/null
+++ b/src/test/lexer/reserved_name.mligo
@@ -0,0 +1 @@
+let object = 1;
\ No newline at end of file
diff --git a/src/test/lexer/reserved_name.religo b/src/test/lexer/reserved_name.religo
new file mode 100644
index 000000000..8803e9edf
--- /dev/null
+++ b/src/test/lexer/reserved_name.religo
@@ -0,0 +1 @@
+let end = 1;
\ No newline at end of file
diff --git a/src/test/lexer/unexpected_character.ligo b/src/test/lexer/unexpected_character.ligo
new file mode 100644
index 000000000..ac31cca58
--- /dev/null
+++ b/src/test/lexer/unexpected_character.ligo
@@ -0,0 +1 @@
+const x: string = ���;
\ No newline at end of file
diff --git a/src/test/lexer/unexpected_character.mligo b/src/test/lexer/unexpected_character.mligo
new file mode 100644
index 000000000..2568a40b6
--- /dev/null
+++ b/src/test/lexer/unexpected_character.mligo
@@ -0,0 +1 @@
+let x = ���;
\ No newline at end of file
diff --git a/src/test/lexer/unexpected_character.religo b/src/test/lexer/unexpected_character.religo
new file mode 100644
index 000000000..2568a40b6
--- /dev/null
+++ b/src/test/lexer/unexpected_character.religo
@@ -0,0 +1 @@
+let x = ���;
\ No newline at end of file
diff --git a/src/test/lexer/unterminated_comment.mligo b/src/test/lexer/unterminated_comment.mligo
new file mode 100644
index 000000000..9f845562c
--- /dev/null
+++ b/src/test/lexer/unterminated_comment.mligo
@@ -0,0 +1 @@
+(* not closed
\ No newline at end of file