Multi-line repl test

Tricky since we need to open a pseudotty to get the repl behavior.
(Piping in a program to stdin goes through a different code path.)

src/jit.cpp

@@ -455,7 +455,7 @@ static int main(int argc, char** argv) {
             main_module = createModule(boxString("__main__"), "<string>");
             rtncode = (RunModule(module, 1) != 0);
         } else {
-            main_module = createModule(boxString("__main__"), fn ? fn : "<string>");
+            main_module = createModule(boxString("__main__"), fn ? fn : "<stdin>");
             rtncode = 0;
             if (fn != NULL) {
                 rtncode = RunMainFromImporter(fn);

src/runtime/traceback.cpp

@@ -61,7 +61,7 @@ void printTraceback(Box* b) {
 
     for (; tb && tb != None; tb = static_cast<BoxedTraceback*>(tb->tb_next)) {
         auto& line = tb->line;
-        fprintf(stderr, "  File \"%s\", line %d, in %s:\n", line.file->c_str(), line.line, line.func->c_str());
+        fprintf(stderr, "  File \"%s\", line %d, in %s\n", line.file->c_str(), line.line, line.func->c_str());
 
         if (line.line < 0)
             continue;

test/tests/multiline_repl.py

+import os
+import pty
+import subprocess
+import sys
+
+def test(s, expected_code=0):
+    pid, fd = pty.fork()
+    if pid == 0:
+        os.execl(sys.executable, sys.executable, '-S')
+
+    written = 0
+    # The same fd is used for reading and writing, so I'm not sure how to signal that it's closed
+    # to the child but still have it be readable by the parent.
+    s += '\nimport os\nos._exit(0)\n'
+    while written < len(s):
+        written += os.write(fd, s[written:])
+
+    _, wcode = os.waitpid(pid, 0)
+
+    print
+    r = os.read(fd, 10240)
+    lines = r.split('\n')
+    while not (lines[0].startswith('Python') or lines[0].startswith('Pyston')):
+        lines.pop(0)
+    if lines[0].startswith('Python'):
+        lines.pop(0)
+    lines.pop(0)
+
+    # Filter out syntax error location lines and make carets consistent:
+    lines = [l.replace('>>> ', '>> ') for l in lines if l.strip() != '^']
+
+    print '\n'.join(lines)
+
+    assert os.WIFEXITED(wcode), wcode
+    code = os.WEXITSTATUS(wcode)
+
+    assert code == expected_code, "Expected %d, got %d" % (expected_code, code)
+
+test("1")
+test("1/0")
+test("import sys; sys.exit(2)", 2)
+test("import sys\nsys.exit(2)", 2)
+test("import sys; sys.exit(\n2)", 2)
+test("class C(object):\n    a=1\nprint C().a", 0)
+test("class C(object):\n    a=1\n\nprint C().a", 0)