Rearrange nre files

tests/stdlib/nre/init.nim

@@ -0,0 +1,36 @@
+import unittest, private/pcre
+include nre
+
+suite "Test NRE initialization":
+  test "correct intialization":
+    check(re("[0-9]+") != nil)
+    check(re("(?i)[0-9]+") != nil)
+
+  test "options":
+    check(extractOptions("(*NEVER_UTF)") ==
+          ("", pcre.NEVER_UTF, true))
+    check(extractOptions("(*UTF8)(*ANCHORED)(*UCP)z") ==
+          ("(*UTF8)(*UCP)z", pcre.ANCHORED, true))
+    check(extractOptions("(*ANCHORED)(*UTF8)(*JAVASCRIPT_COMPAT)z") ==
+          ("(*UTF8)z", pcre.ANCHORED or pcre.JAVASCRIPT_COMPAT, true))
+
+    check(extractOptions("(*NO_STUDY)(") == ("(", 0, false))
+
+    check(extractOptions("(*LIMIT_MATCH=6)(*ANCHORED)z") ==
+          ("(*LIMIT_MATCH=6)z", pcre.ANCHORED, true))
+
+  test "incorrect options":
+    for s in ["CR", "(CR", "(*CR", "(*abc)", "(*abc)CR",
+              "(?i)",
+              "(*LIMIT_MATCH=5", "(*NO_AUTO_POSSESS=5)"]:
+      let ss = s & "(*NEVER_UTF)"
+      check(extractOptions(ss) == (ss, 0, true))
+
+  test "invalid regex":
+    expect(SyntaxError): discard re("[0-9")
+    try:
+      discard re("[0-9")
+    except SyntaxError:
+      let ex = SyntaxError(getCurrentException())
+      check(ex.pos == 4)
+      check(ex.pattern == "[0-9")