diff --git a/README.md b/README.md
index ccdce5b..6d31bda 100644
--- a/README.md
+++ b/README.md
@@ -13,8 +13,8 @@ Increments:
 
 - [X] Integers
 - [X] Binary Operators on Ints
-- [ ] Unary Operators on Ints
-- [ ] Variables and Assignment
+- [X] Unary Operators on Ints
+- [ ] Local Variables and Assignment
 - [ ] Booleans and Comparisons
 - [ ] WriteLn("Hello World") (finally)
 - [ ] Branching (if statements)
@@ -24,3 +24,25 @@ Increments:
 - [ ] Arrays
 - [ ] Records
 - [ ] Pointers 
+
+## Testing
+
+HSPC's approach to testing is to test parity with [fpc](https://www.freepascal.org/).
+This is tested with integration tests comparing the `STDOUT` and
+`EXIT_CODE` of compiled versions of the same pascal code
+(one by `hspc` and one by `fpc`).
+
+To rerun the programs against `fpc`.
+
+```bash
+# from project root
+cd test/sample_programs
+bash generate_goldens.bash
+```
+
+To run the tests.
+
+```bash
+# from project root
+cabal test
+```
diff --git a/src/HSPC/CodeGen.hs b/src/HSPC/CodeGen.hs
index ee5fd92..275b957 100644
--- a/src/HSPC/CodeGen.hs
+++ b/src/HSPC/CodeGen.hs
@@ -20,8 +20,12 @@ generateProgram (Program _ body) = concatMap generateProgram body
 generateProgram (Block body) = concatMap generateProgram body
 generateProgram (Halt ast) =
   generateProgram ast
-    ++ [0x48, 0x89, 0xc7] -- Copy rax to rdi
-    ++ [0xb8, 0x3c, 00, 00, 00] -- mov rax 60 (sys_exit number)
+    -- copy rax -> rdi but maxed out at 255
+    ++ [0xbf, 0xff, 0, 0, 0] -- mov edi 255
+    ++ [0x48, 0x3d, 0xff, 0, 0, 0] -- cmp rax 255
+    ++ [0x48, 0x0f, 0x4c, 0xf8] -- cmovl rax rdi
+    -- exit_group syscall, exit code is in rdi
+    ++ [0xb8, 0x3c, 00, 00, 00] -- mov rax 60
     ++ [0x0f, 0x05] -- Syscall
 generateProgram (IntLiteral i) =
   [0x48, 0xb8] ++ int64ToLE i -- movabs rax i
@@ -37,6 +41,10 @@ generateProgram (Multiply op1 op2) =
     ++ generateProgram op2
     ++ [0x48, 0x0f, 0xaf, 0x04, 0x24] -- imul rax [rsp]
     ++ [0x48, 0x83, 0xc4, 0x08] -- add rsp 8 (release stack space)
+generateProgram (UnaryPlus op) = generateProgram op -- unary + is a nop
+generateProgram (UnaryMinus op) =
+  generateProgram op
+    ++ [0x48, 0xf7, 0xd8]
 generateProgram (IntDivide op1 op2) =
   generateProgram op2
     ++ [0x50] -- push rax
@@ -44,4 +52,4 @@ generateProgram (IntDivide op1 op2) =
     ++ [0x48, 0x99] -- cqo
     ++ [0x48, 0xf7, 0x3c, 0x24] -- idiv qword [rsp]
     ++ [0x48, 0x83, 0xc4, 0x08] -- add rsp 8 (release stack space)
-generateProgram ast = error $ "CodeGen for " ++ show ast ++ "Not implemented"
+generateProgram ast = error $ "CodeGen for " ++ show ast ++ " not implemented"
diff --git a/src/HSPC/Parse.hs b/src/HSPC/Parse.hs
index ef175f5..5699797 100644
--- a/src/HSPC/Parse.hs
+++ b/src/HSPC/Parse.hs
@@ -8,6 +8,8 @@ data AST
   | Block [AST]
   | Identifier String
   | IntLiteral Int64
+  | UnaryPlus AST
+  | UnaryMinus AST
   | Add AST AST
   | IntDivide AST AST
   | Subtract AST AST
@@ -20,7 +22,7 @@ data ParseError
   | ExpectedEndStatement
   | BlockMustStartWithBegin
   | BracketNotClosed
-  | ExpectedOperand
+  | ExpectedOperand String
   | UnmatchedBracket
   | UnexpectedToken HSPCToken
   | ExpectedToken HSPCToken
@@ -88,17 +90,20 @@ parseExpr tok = Left $ NotImplemented tok
 
 -- IntOperand  = Term { ("+" | "-") Term }
 -- Term        = Factor { ("*" | "div") Factor }
--- Factor      = Number | "(" Expression ")"
+-- Factor      = ("+" | "-") Factor | Number | "(" IntOperand ")"
 -- Number      = // an integer
 parseIntOperand :: [HSPCToken] -> Either ParseError AST
 parseIntOperand toks = case breakLastOuter (`elem` [PlusTok, MinusTok]) toks of
+  -- starts with +-
+  ([], after) -> parseTerm after
+  -- doesn't contain +-
   (before, []) -> parseTerm before
-  (_, [PlusTok]) -> Left ExpectedOperand
+  (_, [PlusTok]) -> Left $ ExpectedOperand "Expected operand after +"
   (before, PlusTok : after) -> do
     left <- parseIntOperand before
     right <- parseTerm after
     return $ Add left right
-  (_, [MinusTok]) -> Left ExpectedOperand
+  (_, [MinusTok]) -> Left $ ExpectedOperand "Expected operand after -"
   (before, MinusTok : after) -> do
     left <- parseIntOperand before
     right <- parseTerm after
@@ -108,12 +113,12 @@ parseIntOperand toks = case breakLastOuter (`elem` [PlusTok, MinusTok]) toks of
 parseTerm :: [HSPCToken] -> Either ParseError AST
 parseTerm toks = case breakLastOuter (`elem` [IntDivideTok, MultiplyTok]) toks of
   (before, []) -> parseFactor before
-  (_, [IntDivideTok]) -> Left ExpectedOperand
+  (_, [IntDivideTok]) -> Left $ ExpectedOperand "Expected operand after 'div'"
   (before, IntDivideTok : after) -> do
     left <- parseIntOperand before
     right <- parseFactor after
     return $ IntDivide left right
-  (_, [MultiplyTok]) -> Left ExpectedOperand
+  (_, [MultiplyTok]) -> Left $ ExpectedOperand "Expected operand after *"
   (before, MultiplyTok : after) -> do
     left <- parseIntOperand before
     right <- parseFactor after
@@ -122,10 +127,16 @@ parseTerm toks = case breakLastOuter (`elem` [IntDivideTok, MultiplyTok]) toks o
 
 parseFactor :: [HSPCToken] -> Either ParseError AST
 parseFactor [LiteralIntTok n] = Right $ IntLiteral n
+parseFactor (PlusTok : xs) = do
+  operand <- parseFactor xs
+  return $ UnaryPlus operand
+parseFactor (MinusTok : xs) = do
+  operand <- parseFactor xs
+  return $ UnaryMinus operand
 parseFactor (OpenBracketTok : xs) = do
   (inside, remaining) <- splitToMatchingBracket xs
   case remaining of
     [] -> parseIntOperand inside
     (tok : _) -> Left $ UnexpectedToken tok
 parseFactor (tok : _) = Left $ UnexpectedToken tok
-parseFactor _ = Left ExpectedOperand
+parseFactor [] = Left $ ExpectedOperand "Expected operand"
diff --git a/test/Main.hs b/test/Main.hs
index 42f0554..a207c44 100644
--- a/test/Main.hs
+++ b/test/Main.hs
@@ -12,8 +12,9 @@ import Test.Tasty.HUnit
 
 data TestSpec = TestSpec
   { name :: String,
-    srcPath :: FilePath,
-    goldenPath :: FilePath,
+    -- There should be <testName>.pas and <testName>.golden
+    --  in sampleProgramsLocation
+    testName :: FilePath,
     expectedExit :: Int
   }
 
@@ -22,13 +23,16 @@ sampleProgramsLocation = "test/sample_programs/"
 
 testSuite :: [TestSpec]
 testSuite =
-  [ TestSpec "Exit code 0" "ints_0_exit_code.pas" "/dev/null" 0,
-    TestSpec "Exit code 255" "ints_255_exit_code.pas" "/dev/null" 255,
-    TestSpec "Halt after Halt" "ints_halt_after_halt.pas" "/dev/null" 0,
-    TestSpec "Add literal ints" "operators_add_two_ints.pas" "/dev/null" 200,
-    TestSpec "Multiply literal ints" "operators_multiply_two_ints.pas" "/dev/null" 40,
-    TestSpec "Divide(div) literal ints" "operators_divide_two_ints.pas" "/dev/null" 2,
-    TestSpec "Brackets with literal ints" "operators_brackets.pas" "/dev/null" 26
+  [ TestSpec "Exit code 0" "ints_0_exit_code" 0,
+    TestSpec "Exit code 255" "ints_255_exit_code" 255,
+    TestSpec "Exit code > 255" "ints_big_exit_code" 255,
+    TestSpec "Halt after Halt" "ints_halt_after_halt" 0,
+    TestSpec "Add literal ints" "operators_add_two_ints" 200,
+    TestSpec "Multiply literal ints" "operators_multiply_two_ints" 40,
+    TestSpec "Divide(div) literal ints" "operators_divide_two_ints" 2,
+    TestSpec "Brackets with literal ints" "operators_brackets" 26,
+    TestSpec "Unary minus with literal ints" "operators_unary_minus_int" 75,
+    TestSpec "Unary plus with literal ints" "operators_unary_plus_int" 25
   ]
 
 main :: IO ()
@@ -40,7 +44,7 @@ main =
 
 runIntegrationTest :: TestSpec -> Assertion
 runIntegrationTest spec = do
-  source <- readFile (sampleProgramsLocation ++ srcPath spec)
+  source <- readFile (sampleProgramsLocation ++ testName spec ++ ".pas")
 
   case compile source of
     Left err -> assertFailure $ "Compilation failed: " ++ show err
@@ -56,12 +60,12 @@ runIntegrationTest spec = do
             ExitFailure n -> n
 
       assertEqual
-        ("Exit code mismatch for " ++ srcPath spec ++ "\nStderr: " ++ stderr)
+        ("Exit code mismatch for " ++ testName spec ++ "\nStderr: " ++ stderr)
         (expectedExit spec)
         actualCode
 
-      goldenOut <- readFile (goldenPath spec)
+      goldenOut <- readFile (sampleProgramsLocation ++ testName spec ++ ".golden")
       assertEqual
-        ("StdOut mismatch for " ++ srcPath spec ++ "\nStderr: " ++ stderr)
+        ("StdOut mismatch for " ++ testName spec ++ "\nStderr: " ++ stderr)
         goldenOut
         stdout
diff --git a/test/sample_programs/generate_goldens.bash b/test/sample_programs/generate_goldens.bash
new file mode 100644
index 0000000..1d378b1
--- /dev/null
+++ b/test/sample_programs/generate_goldens.bash
@@ -0,0 +1,47 @@
+#!/bin/bash
+# Note: AI generated by gemini
+
+# Define formatting for the table output
+# %-30s means left-align string with 30 chars width
+FORMAT="%-30s | %-10s\n"
+
+# Print Table Header
+printf "$FORMAT" "Test Name" "Exit Code"
+echo "-------------------------------+-----------"
+
+# Loop through all .pas files in the current directory
+for source_file in *.pas; do
+    
+    # Handle case where no .pas files exist
+    [ -e "$source_file" ] || continue
+
+    # Extract the filename without the extension (e.g., test1.pas -> test1)
+    test_name="${source_file%.*}"
+
+    # 1. Compile with Free Pascal (fpc)
+    # -v0 suppresses the fpc logo and verbose messages to keep stdout clean
+    # We redirect compiler output to /dev/null so it doesn't clutter the table
+    if fpc -v0 "$source_file" > /dev/null 2>&1; then
+        
+        # 2. Run the executable
+        # Redirect stdout to the golden file
+        # Stderr is left visible (or you can redirect it to /dev/null)
+        ./"$test_name" > "${test_name}.golden"
+        
+        # 3. Capture the exit code of the executable
+        exit_code=$?
+        
+        # 4. Print the row in the table
+        printf "$FORMAT" "$test_name" "$exit_code"
+
+        # 5. Cleanup (Optional)
+        # fpc creates an executable and an object file (.o). 
+        # We remove them to keep the directory clean.
+        rm -f "$test_name" "${test_name}.o" 
+
+    else
+        # If fpc failed to compile
+        printf "$FORMAT" "$test_name" "COMPILE ERR"
+    fi
+
+done
diff --git a/test/sample_programs/ints_0_exit_code.golden b/test/sample_programs/ints_0_exit_code.golden
new file mode 100644
index 0000000..e69de29
diff --git a/test/sample_programs/ints_255_exit_code.golden b/test/sample_programs/ints_255_exit_code.golden
new file mode 100644
index 0000000..e69de29
diff --git a/test/sample_programs/ints_big_exit_code.golden b/test/sample_programs/ints_big_exit_code.golden
new file mode 100644
index 0000000..e69de29
diff --git a/test/sample_programs/ints_big_exit_code.pas b/test/sample_programs/ints_big_exit_code.pas
new file mode 100644
index 0000000..0d4b0cd
--- /dev/null
+++ b/test/sample_programs/ints_big_exit_code.pas
@@ -0,0 +1,5 @@
+program HaltExample;
+
+begin
+    halt(10000); 
+end.
diff --git a/test/sample_programs/ints_halt_after_halt.golden b/test/sample_programs/ints_halt_after_halt.golden
new file mode 100644
index 0000000..e69de29
diff --git a/test/sample_programs/operators_add_two_ints.golden b/test/sample_programs/operators_add_two_ints.golden
new file mode 100644
index 0000000..e69de29
diff --git a/test/sample_programs/operators_brackets.golden b/test/sample_programs/operators_brackets.golden
new file mode 100644
index 0000000..e69de29
diff --git a/test/sample_programs/operators_divide_two_ints.golden b/test/sample_programs/operators_divide_two_ints.golden
new file mode 100644
index 0000000..e69de29
diff --git a/test/sample_programs/operators_multiply_two_ints.golden b/test/sample_programs/operators_multiply_two_ints.golden
new file mode 100644
index 0000000..e69de29
diff --git a/test/sample_programs/operators_unary_minus_int.golden b/test/sample_programs/operators_unary_minus_int.golden
new file mode 100644
index 0000000..e69de29
diff --git a/test/sample_programs/operators_unary_minus_int.pas b/test/sample_programs/operators_unary_minus_int.pas
new file mode 100644
index 0000000..6df4af2
--- /dev/null
+++ b/test/sample_programs/operators_unary_minus_int.pas
@@ -0,0 +1,5 @@
+program UnaryMinusTest;
+
+begin
+    halt(100+(-25)); 
+end.
diff --git a/test/sample_programs/operators_unary_plus_int.golden b/test/sample_programs/operators_unary_plus_int.golden
new file mode 100644
index 0000000..e69de29
diff --git a/test/sample_programs/operators_unary_plus_int.pas b/test/sample_programs/operators_unary_plus_int.pas
new file mode 100644
index 0000000..cc26d2f
--- /dev/null
+++ b/test/sample_programs/operators_unary_plus_int.pas
@@ -0,0 +1,5 @@
+program UnaryPlusTest;
+
+begin
+    halt(+(-(-25))); 
+end.