diff --git a/.gitignore b/.gitignore
index 227ac5b..949cae3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,6 +11,7 @@ htmldocs/
 # JAPL
 
 src/japl
+src/compiler
 tests/runtests
 
 # MacOS
diff --git a/src/stdlib.nim b/src/stdlib.nim
index 531c9a3..ff00ff6 100644
--- a/src/stdlib.nim
+++ b/src/stdlib.nim
@@ -31,8 +31,12 @@ proc natPrint(args: seq[ptr Obj]): tuple[ok: bool, result: ptr Obj] =
     ## is passed, they will be printed separated
     ## by a space
     var res = ""
-    for arg in args:
-        res = res & arg.stringify() & " "
+    for i in countup(0, args.high()):
+        let arg = args[i]
+        if i < args.high():
+            res = res & arg.stringify() & " "
+        else:
+            res = res & arg.stringify()
     echo res
     return (ok: true, result: asNil())
 
diff --git a/tests/japl/arithmetic.jpl b/tests/japl/arithmetic.jpl
new file mode 100644
index 0000000..7923450
--- /dev/null
+++ b/tests/japl/arithmetic.jpl
@@ -0,0 +1,19 @@
+//int arithmetic
+
+print(7+5); //output:12
+print(-8); //output:-8
+print(5-8); //output:-3
+print(1+1+1+1+1); //output:5
+print(1-1+1-1+1-1); //output:0
+print(2*3+2);//output:8
+print(2+3*2);//output:8
+print(3+2*7);//output:17
+print(2-9*5);//output:-43
+print(2*9-5);//output:13
+print(2**5);//output:32
+print(3**3);//output:27
+print(3**3*2);//output:54
+print(8+2**4);//output:24
+print(2+7*2+4);//output:20
+print(1-2**2*5);//output:-19
+print(7*-2**3+4*7);//output:-28
diff --git a/tests/runtests.nim b/tests/runtests.nim
index 29601e8..815da55 100644
--- a/tests/runtests.nim
+++ b/tests/runtests.nim
@@ -18,6 +18,21 @@ proc compileExpectedOutput(path: string): string =
         if line =~ re"^.*//output:(.*)$":
             result &= matches[0] & "\n"
 
+proc deepComp(left, right: string): tuple[same: bool, place: int] =
+    result.same = true
+    if left.high() != right.high():
+        result.same = false
+    for i in countup(0, left.high()):
+        result.place = i
+        if i > right.high():
+            # already false bc of the len check at the beginning
+            # already correct place bc it's updated every i
+            return
+        if left[i] != right[i]:
+            result.same = false
+            return
+
+
 var testsDir = "tests" / "japl"
 var japlExec = "src" / "japl"
 
@@ -62,19 +77,26 @@ for file in walkDir(testsDir):
                 break singularTest
 
         log &"Running test {file.path}"
+        if fileExists("testoutput.txt"):
+            removeFile("testoutput.txt") # in case this crashed
         discard execShellCmd(&"{japlExec} {file.path} >>testoutput.txt")
-        let expectedOutput = compileExpectedOutput(file.path)
+        let expectedOutput = compileExpectedOutput(file.path).replace(re"(\n*)$", "")
         let realOutputFile = open("testoutput.txt", fmRead)
-        let realOutput = realOutputFile.readAll()
+        let realOutput = realOutputFile.readAll().replace(re"([\n\r]*)$", "")
         realOutputFile.close()
         removeFile("testoutput.txt")
-        if expectedOutput == realOutput:
+        let comparison = deepComp(expectedOutput, realOutput)
+        if comparison.same:
             log &"Successful test {file.path}"
         else:
             detail &"Expected output:\n{expectedOutput}\n"
             detail &"Received output:\n{realOutput}\n"
+            detail &"Mismatch at pos {comparison.place}"
+            if comparison.place > expectedOutput.high() or 
+                comparison.place > realOutput.high():
+                detail &"Length mismatch"
+            else:
+                detail &"Expected is '{expectedOutput[comparison.place]}' while received '{realOutput[comparison.place]}'"
             log &"Test failed {file.path}, check 'testresults.txt' for details"
             
-
-
-
+testResultsFile.close()