tests: Split large tests into smaller files, to run with a small heap.

All tests in basics/ directory can now run and pass using 64-bit unix
port with only a 16k heap (./run-tests --heapsize 16k).  Tests in this
directory should remain small so they can be used for ports with a
small heap.

tests/basics/string_format_error.py

@@ -0,0 +1,90 @@
+# tests for errors in {} format string
+
+try:
+    '{0:0}'.format('zzz')
+except (ValueError):
+    print('ValueError')
+
+try:
+    '{1:}'.format(1)
+except IndexError:
+    print('IndexError')
+
+try:
+    '}'.format('zzzz')
+except ValueError:
+    print('ValueError')
+
+# end of format parsing conversion specifier
+try:
+    '{!'.format('a')
+except ValueError:
+    print('ValueError')
+
+# unknown conversion specifier
+try:
+    'abc{!d}'.format('1')
+except ValueError:
+    print('ValueError')
+
+try:
+    '{abc'.format('zzzz')
+except ValueError:
+    print('ValueError')
+
+# expected ':' after specifier
+try:
+    '{!s :}'.format(2)
+except ValueError:
+    print('ValueError')
+
+try:
+    '{}{0}'.format(1, 2)
+except ValueError:
+    print('ValueError')
+
+try:
+    '{1:}'.format(1)
+except IndexError:
+    print('IndexError')
+
+try:
+    '{ 0 :*^10}'.format(12)
+except KeyError:
+    print('KeyError')
+
+try:
+    '{0}{}'.format(1)
+except ValueError:
+    print('ValueError')
+
+try:
+    '{}{}'.format(1)
+except IndexError:
+    print('IndexError')
+
+try:
+    '{0:+s}'.format('1')
+except ValueError:
+    print('ValueError')
+
+try:
+    '{0:+c}'.format(1)
+except ValueError:
+    print('ValueError')
+
+try:
+    '{0:s}'.format(1)
+except ValueError:
+    print('ValueError')
+
+try:
+    '{:*"1"}'.format('zz')
+except ValueError:
+    print('ValueError')
+
+# unknown format code for str arg
+try:
+    '{:X}'.format('zz')
+except ValueError:
+    print('ValueError')