nimpretty: proper command line handling; added tests; travis ensures these stay green

nimpretty/tester.nim

@@ -0,0 +1,29 @@
+# Small program that runs the test cases
+
+import strutils, os
+
+const
+  dir = "nimpretty/tests/"
+
+var
+  failures = 0
+
+proc test(infile, outfile: string) =
+  if execShellCmd("nimpretty -o:$2 --backup:off $1" % [infile, outfile]) != 0:
+    quit("FAILURE")
+  let nimFile = splitFile(infile).name
+  let expected = dir / "expected" / nimFile & ".nim"
+  let produced = dir / nimFile & ".pretty"
+  if strip(readFile(expected)) != strip(readFile(produced)):
+    echo "FAILURE: files differ: ", nimFile
+    discard execShellCmd("diff -uNdr " & produced & " " & expected)
+    failures += 1
+  else:
+    echo "SUCCESS: files identical: ", nimFile
+
+for t in walkFiles(dir / "*.nim"):
+  let res = t.changeFileExt("pretty")
+  test(t, res)
+  removeFile(res)
+
+if failures > 0: quit($failures & " failures occurred.")