Feature: Add --trackDir option

With this commit, we can now establish a beginning state by specifying:
- a track directory
- a problem-specifications directory
- the offline mode

This allows us to do black-box testing of the release binary, running
something like:
    canonical_data_syncer -t /tmp/python -p /tmp/my_prob_specs --offline
and then asserting that the changes made are as expected.

Closes: exercism#50

README.md

@@ -16,6 +16,7 @@ Options:
   -v, --verbosity <verbosity>  The verbosity of output. Allowed values: q[uiet], n[ormal], d[etailed]
   -p, --probSpecsDir <dir>     Use this `problem-specifications` directory, rather than cloning temporarily
   -o, --offline                Do not check that the directory specified by `-p, --probSpecsDir` is up-to-date
+  -t, --trackDir <dir>         Specify a track directory to use instead of the current directory
   -h, --help                   Show this help message and exit
   --version                    Show this tool's version information and exit
 ```

src/cli.nim

@@ -18,10 +18,11 @@ type
     verbosity*: Verbosity
     probSpecsDir*: Option[string]
     offline*: bool
+    trackDir*: Option[string]
 
   Opt = enum
     optExercise, optCheck, optMode, optVerbosity, optProbSpecsDir, optOffline,
-    optHelp, optVersion
+    optTrackDir, optHelp, optVersion
 
   OptKey = tuple
     short: string
@@ -37,6 +38,7 @@ const
     ("v", "verbosity"),
     ("p", "probSpecsDir"),
     ("o", "offline"),
+    ("t", "trackDir"),
     ("h", "help"),
     ("_", "version"), # No short option for `--version`
   ]
@@ -61,6 +63,7 @@ Options:
   -{optVerbosity.short}, --{optVerbosity.long} <verbosity>  The verbosity of output. Allowed values: q[uiet], n[ormal], d[etailed]
   -{optProbSpecsDir.short}, --{optProbSpecsDir.long} <dir>     Use this `problem-specifications` directory, rather than cloning temporarily
   -{optOffline.short}, --{optOffline.long}                Do not check that the directory specified by `-p, --probSpecsDir` is up-to-date
+  -{optTrackDir.short}, --{optTrackDir.long} <dir>         Specify a track directory to use instead of the current directory
   -{optHelp.short}, --{optHelp.long}                   Show this help message and exit
   --{optVersion.long}                    Show this tool's version information and exit"""
 
@@ -146,6 +149,9 @@ proc processCmdLine*: Conf =
         result.probSpecsDir = some(val)
       of optOffline.short, optOffline.long:
         result.offline = true
+      of optTrackDir.short, optTrackDir.long:
+        showErrorForMissingVal(kind, key, val)
+        result.trackDir = some(val)
       of optHelp.short, optHelp.long:
         showHelp()
       of optVersion.short, optVersion.long:

src/tracks.nim

@@ -83,5 +83,9 @@ proc findTrackExercises(repo: TrackRepo, conf: Conf): seq[TrackExercise] =
       result.add(newTrackExercise(repoExercise))
 
 proc findTrackExercises*(conf: Conf): seq[TrackExercise] =
-  let trackRepo = newTrackRepo()
+  let trackRepo =
+    if conf.trackDir.isSome():
+      TrackRepo(dir: conf.trackDir.get())
+    else:
+      newTrackRepo()
   trackRepo.findTrackExercises(conf)