diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,14 @@
 # Revision history for staversion
 
+## 0.2.2.0  -- 2018-07-01
+
+* Add `--stack` and `--stack-default` (`-S`) options (#4).
+* Now `--stack-default` option is implied if there is no package source specified (#4).
+* Support `aeson-1.4` and `megaparsec-6.5.0`.
+* [Bug fix] `-H` option: It now proceed if hackage returns 404
+  error. That is probably because the user specified a package not on
+  hackage, so it's not fatal.
+
 ## 0.2.1.4  -- 2018-03-26
 
 * Support `base-4.11.0.0`.
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -32,6 +32,15 @@
 
 staversion first reads build plan YAML files that are stored locally in your computer, then it tries to fetch them over network.
 
+## Package version of your current stack project
+
+If you omit `--resolver` (`-r`) option (or explicitly specify `--stack-default` (`-S`) option), staversion reads `stack.yaml` of your current project, and searches for package versions in the resolver specified in the `stack.yaml`.
+
+    $ staversion conduit
+    ------ default stack resolver (lts-10.8)
+    conduit ==1.2.13.1
+
+
 ## Package version in Hackage
 
 You can also look up the latest version numbers hosted on hackage with `--hackage` (`-H`) option.
diff --git a/src/Staversion/Internal/BuildPlan.hs b/src/Staversion/Internal/BuildPlan.hs
--- a/src/Staversion/Internal/BuildPlan.hs
+++ b/src/Staversion/Internal/BuildPlan.hs
@@ -12,6 +12,7 @@
          buildPlanSource,
          BuildPlanManager,
          newBuildPlanManager,
+         manStackCommand,
          loadBuildPlan,
          -- * Low-level APIs
          BuildPlanMap,
@@ -61,6 +62,7 @@
     PartialResolver(..), ExactResolver(..),
     fetchBuildPlanYAML
   )
+import qualified Staversion.Internal.BuildPlan.StackYaml as StackYaml
 import Staversion.Internal.BuildPlan.Version (unVersionJSON)
 import Staversion.Internal.Version (Version)
 
@@ -103,12 +105,19 @@
 -- | Stateful manager for 'BuildPlan's.
 data BuildPlanManager =
   BuildPlanManager { manBuildPlanDir :: FilePath,
-                     -- ^ path to the directory where build plans are hold.
+                     -- ^ (accessor function) path to the directory
+                     -- where build plans are hold.
                      manHttpManager :: Maybe Manager,
-                     -- ^ low-level HTTP connection manager. If 'Nothing', it won't fetch build plans over the network.
+                     -- ^ (accessor function) low-level HTTP
+                     -- connection manager. If 'Nothing', it won't
+                     -- fetch build plans over the network.
                      manDisambiguator :: IORef (Maybe Disambiguator),
-                     -- ^ cache of resolver disambigutor
-                     manLogger :: Logger
+                     -- ^ (accessor function) cache of resolver
+                     -- disambigutor
+                     manLogger :: Logger,
+                     manStackCommand :: String
+                     -- ^ (accessor function) Shell command for the
+                     -- @stack@ tool.
                    }
 
 newBuildPlanManager :: FilePath -- ^ path to the directory where build plans are hold.
@@ -123,7 +132,8 @@
   return $ BuildPlanManager { manBuildPlanDir = plan_dir,
                               manHttpManager = mman,
                               manDisambiguator = disam,
-                              manLogger = logger
+                              manLogger = logger,
+                              manStackCommand = "stack"
                             }
 
 type LoadM = ExceptT ErrorMsg IO
@@ -167,9 +177,24 @@
     build_plan_map <- (mconcat . zipWith registeredVersionToBuildPlanMap names) <$> mapM (doFetch http_man) names
     return $ BuildPlan { buildPlanMap = build_plan_map, buildPlanSource = SourceHackage }
   logDebug' msg = liftIO $ logDebug (manLogger man) msg
+  logWarn' msg = liftIO $ logWarn (manLogger man) msg
   doFetch http_man name = do
     logDebug' ("Ask hackage for the latest version of " ++ unpack name)
-    ExceptT $ fetchPreferredVersions http_man name
+    reg_ver <- ExceptT $ fetchPreferredVersions http_man name
+    case latestVersion reg_ver of
+     Nothing -> logWarn' ("Cannot find package version of " ++ unpack name ++ ". Maybe it's not on hackage.")
+     Just _ -> return ()
+    return reg_ver
+loadBuildPlan man names (SourceStackYaml file) = do
+  eresolver <- StackYaml.readResolver file
+  case eresolver of
+   Left err -> return $ Left err
+   Right resolver -> loadBuildPlan man names (SourceStackage resolver)
+loadBuildPlan man names SourceStackDefault = do
+  efile <- StackYaml.configLocation (manLogger man) (manStackCommand man)
+  case efile of
+   Left err -> return $ Left err
+   Right f -> loadBuildPlan man names (SourceStackYaml f)
 
 loadBuildPlan_stackageLocalFile :: BuildPlanManager -> Resolver -> LoadM BuildPlan
 loadBuildPlan_stackageLocalFile man resolver = ExceptT $ catchJust handleIOError doLoad (return . Left) where
diff --git a/src/Staversion/Internal/BuildPlan/Hackage.hs b/src/Staversion/Internal/BuildPlan/Hackage.hs
--- a/src/Staversion/Internal/BuildPlan/Hackage.hs
+++ b/src/Staversion/Internal/BuildPlan/Hackage.hs
@@ -22,7 +22,7 @@
 
 import Staversion.Internal.BuildPlan.Version (unVersionJSON)
 import Staversion.Internal.Query (ErrorMsg, PackageName)
-import Staversion.Internal.HTTP (Manager, fetchURL, OurHttpException)
+import Staversion.Internal.HTTP (Manager, fetchURL, OurHttpException, asStatusFailureException)
 import Staversion.Internal.Version (Version)
 
 data RegisteredVersions = RegisteredVersions { regPreferredVersions :: [Version]
@@ -47,5 +47,11 @@
 fetchPreferredVersions man text_name = Exception.handle handler $ parsePreferredVersionsJSON <$> fetchURL man url where
   name = unpack text_name
   url = "http://hackage.haskell.org/package/" ++ name ++ "/preferred.json"
-  handler :: OurHttpException -> IO (Either ErrorMsg a)
-  handler e = return $ Left ("HTTP error while fetching versions of " ++ name ++ " in hackage: " ++ show e)
+  handler :: OurHttpException -> IO (Either ErrorMsg RegisteredVersions)
+  handler e = case asStatusFailureException e of
+    Nothing -> return $ Left err
+    Just code -> case code of
+      404 -> return $ Right $ RegisteredVersions []
+      _ -> return $ Left err
+    where
+      err = "HTTP error while fetching versions of " ++ name ++ " in hackage: " ++ show e
diff --git a/src/Staversion/Internal/BuildPlan/StackYaml.hs b/src/Staversion/Internal/BuildPlan/StackYaml.hs
new file mode 100644
--- /dev/null
+++ b/src/Staversion/Internal/BuildPlan/StackYaml.hs
@@ -0,0 +1,99 @@
+-- |
+-- Module: Staversion.Internal.BuildPlan.StackYaml
+-- Description: Get PackageSource from stack.yaml
+-- Maintainer: Toshio Ito <debug.ito@gmail.com>
+--
+-- __This is an internal module. End-users should not use it.__
+--
+-- This module is meant to be exposed only to
+-- "Staversion.Internal.BuildPlan" and test modules.
+module Staversion.Internal.BuildPlan.StackYaml
+       ( readResolver,
+         configLocation,
+         configLocationFromText
+       ) where
+
+import Control.Applicative (empty, many, some)
+import Control.Monad (void, when)
+import Data.Char (isSpace)
+import Data.Monoid ((<>))
+import Data.Yaml (FromJSON(..), Value(..), (.:), decodeEither)
+import Data.Text (Text, pack)
+import qualified Data.Text as T
+import qualified Data.ByteString as BS
+import System.Exit (ExitCode(ExitFailure))
+import System.Process
+  ( shell, readCreateProcessWithExitCode
+  )
+
+import Staversion.Internal.Log (Logger, logWarn, logDebug)
+import Staversion.Internal.Query (Resolver, ErrorMsg)
+import Staversion.Internal.Megaparsec (Parser, runParser, satisfy, space)
+
+newtype Resolver' = Resolver' { unResolver' :: Resolver }
+                  deriving (Show,Eq,Ord)
+
+instance FromJSON Resolver' where
+  parseJSON (Object o) = fmap Resolver' $ o .: "resolver"
+  parseJSON _ = empty
+
+-- | Read the @resolver@ field in stack.yaml.
+readResolver :: FilePath -- ^ path to stack.yaml
+             -> IO (Either ErrorMsg Resolver)
+readResolver file = fmap (fmap unResolver' . decodeEither) $ BS.readFile file
+
+-- | Get the path to stack.yaml that @stack@ uses as the current
+-- config.
+configLocation :: Logger
+               -> String -- ^ shell command for @stack@
+               -> IO (Either ErrorMsg FilePath)
+configLocation logger command = do
+  pout <- getProcessOutput logger command
+  case configLocationFromText =<< pout of
+   e@(Right path) -> logDebug logger ("Project stack config: " <> path) >> return e
+   e -> return e
+
+getProcessOutput :: Logger -> String -> IO (Either ErrorMsg Text)
+getProcessOutput logger command = handleResult =<< readCreateProcessWithExitCode cmd ""
+  where
+    cmd_str = command <> " path"
+    cmd = shell cmd_str
+    warnErr err = when (length err /= 0) $ logWarn logger err
+    handleResult (code, out, err) = do
+      case code of
+       ExitFailure c -> do
+         let code_err = "'" <> cmd_str <> "' returns non-zero exit code: " <> show c <> "."
+             hint = "It requires the 'stack' tool. Maybe you have to specify the command by --stack-command option."
+         logWarn logger code_err
+         warnErr err
+         return $ Left (code_err <> "\n" <> hint)
+       _ -> do
+         warnErr err
+         return $ Right $ pack out
+
+configLocationFromText :: Text -> Either ErrorMsg FilePath
+configLocationFromText input = toEither $ findField =<< T.lines input
+  where
+    fieldName = "config-location"
+    findField :: Text -> [FilePath]
+    findField line = do
+      (fname, fvalue) <- maybe [] return $ parseField line
+      if fname == fieldName
+        then return $ T.unpack fvalue
+        else []
+    toEither :: [FilePath] -> Either ErrorMsg FilePath
+    toEither [] = Left ("Cannot find '" <> T.unpack fieldName <> "' field in stack path")
+    toEither (r:_) = Right r
+    parseField :: Text -> Maybe (Text, Text)
+    parseField = either (const Nothing) return . runParser parser ""
+    parser :: Parser (Text,Text)
+    parser = do
+      space
+      fname <- term
+      void $ many $ satisfy isSep
+      fval <- term
+      return (fname, fval)
+      where
+        isSep c = c == ':' || isSpace c
+        term = fmap T.pack $ some $ satisfy (not . isSep)
+      
diff --git a/src/Staversion/Internal/Command.hs b/src/Staversion/Internal/Command.hs
--- a/src/Staversion/Internal/Command.hs
+++ b/src/Staversion/Internal/Command.hs
@@ -7,10 +7,11 @@
 module Staversion.Internal.Command
        ( Command(..),
          parseCommandArgs,
-         defFormatConfig
+         defFormatConfig,
+         _parseCommandStrings
        ) where
 
-import Control.Applicative ((<$>), (<*>), optional, some, (<|>))
+import Control.Applicative ((<$>), (<*>), optional, some, (<|>), many)
 import Data.Function (on)
 import Data.Monoid (mconcat, (<>))
 import Data.Text (pack)
@@ -40,6 +41,8 @@
 data Command =
   Command { commBuildPlanDir :: FilePath,
             -- ^ path to the directory where build plan files are stored.
+            commStackCommand :: String,
+            -- ^ shell command to invoke @stack@ tool.
             commLogger :: Logger,
             -- ^ the logger
             commSources :: [PackageSource],
@@ -65,7 +68,7 @@
     return $ home </> ".stack" </> "build-plan"
 
 commandParser :: DefCommand -> Opt.Parser Command
-commandParser def_comm = Command <$> build_plan_dir <*> logger <*> sources
+commandParser def_comm = Command <$> build_plan_dir <*> stack_command <*> logger <*> sources
                          <*> queries <*> network <*> aggregate <*> format_config where
   logger = makeLogger <$> is_verbose
   makeLogger True = defaultLogger { loggerThreshold = Just LogDebug }
@@ -81,7 +84,12 @@
                                Opt.value (defBuildPlanDir def_comm),
                                Opt.showDefault
                              ]
-  sources = some $ resolver <|> hackage
+  withDefault :: Functor m => [a] -> m [a] -> m [a]
+  withDefault def_vals = fmap applyDef
+    where
+      applyDef [] = def_vals
+      applyDef vs = vs
+  sources = withDefault [SourceStackDefault] $ many $ resolver <|> hackage <|> stack_explicit <|> stack_default
   resolver = fmap SourceStackage $ Opt.strOption
              $ mconcat [ Opt.long "resolver",
                          Opt.short 'r',
@@ -93,6 +101,20 @@
                         Opt.short 'H',
                         Opt.help "Search hackage.org for the latest version."
                       ]
+  stack_explicit = fmap SourceStackYaml $ Opt.strOption
+                   $ mconcat [ Opt.long "stack",
+                               Opt.help ( "Path to stack.yaml file."
+                                          ++ " It searches for package versions of the resolver of the specified stack.yaml file."
+                                        ),
+                               Opt.metavar "FILE"
+                             ]
+  stack_default = Opt.flag' SourceStackDefault
+                  $ mconcat [ Opt.long "stack-default",
+                              Opt.short 'S',
+                              Opt.help ( "Search the resolver that 'stack' command would use by default."
+                                         ++ " This option is implied if there is no options about package source (e.g. -r and -H)."
+                                       )
+                            ]
   queries = some $ parseQuery <$> (query_package <|> query_cabal)
   query_package = Opt.strArgument
                   $ mconcat [ Opt.help "Name of package whose version you want to check.",
@@ -119,6 +141,13 @@
                                Opt.helpDoc $ Just $ docFormatVersions "FORMAT",
                                Opt.value $ fconfFormatVersion defFormatConfig
                              ]
+  stack_command = Opt.strOption
+                  $ mconcat [ Opt.long "stack-command",
+                              Opt.help "Shell command for stack tool.",
+                              Opt.metavar "COMMAND",
+                              Opt.value "stack",
+                              Opt.showDefault
+                            ]
 
 maybeReader :: String -> (String -> Maybe a) -> Opt.ReadM a
 maybeReader metavar mfunc = do
@@ -208,3 +237,12 @@
 
 parseCommandArgs :: IO Command
 parseCommandArgs = Opt.execParser . programDescription . commandParser =<< defCommand
+
+-- | Just for testing.
+_parseCommandStrings :: [String] -> IO (Maybe Command)
+_parseCommandStrings args = fmap (doParse . programDescription . commandParser) defCommand
+  where
+    doParse pinfo = Opt.getParseResult $ Opt.execParserPure prefs pinfo args
+    prefs = Opt.prefs mempty
+
+
diff --git a/src/Staversion/Internal/Exec.hs b/src/Staversion/Internal/Exec.hs
--- a/src/Staversion/Internal/Exec.hs
+++ b/src/Staversion/Internal/Exec.hs
@@ -24,7 +24,7 @@
 import Staversion.Internal.BuildPlan
   ( BuildPlan, packageVersion, buildPlanSource,
     newBuildPlanManager, loadBuildPlan,
-    BuildPlanManager
+    BuildPlanManager, manStackCommand
   )
 import Staversion.Internal.Command
   ( parseCommandArgs,
@@ -64,10 +64,15 @@
 processCommand :: Command -> IO [Result]
 processCommand = _processCommandWithCustomBuildPlanManager return
 
+makeBuildPlanManager :: Command -> IO BuildPlanManager
+makeBuildPlanManager comm = do
+  man <- newBuildPlanManager (commBuildPlanDir comm) (commLogger comm) (commAllowNetwork comm)
+  return $ man { manStackCommand = commStackCommand comm }
+
 _processCommandWithCustomBuildPlanManager :: (BuildPlanManager -> IO BuildPlanManager) -> Command -> IO [Result]
 _processCommandWithCustomBuildPlanManager customBPM comm = impl where
   impl = do
-    bp_man <- customBPM =<< newBuildPlanManager (commBuildPlanDir comm) (commLogger comm) (commAllowNetwork comm)
+    bp_man <- customBPM =<< makeBuildPlanManager comm
     query_pairs <- resolveQueries' logger $ commQueries comm
     fmap concat $ mapM (processQueriesIn bp_man query_pairs) $ commSources comm
   logger = commLogger comm
diff --git a/src/Staversion/Internal/HTTP.hs b/src/Staversion/Internal/HTTP.hs
--- a/src/Staversion/Internal/HTTP.hs
+++ b/src/Staversion/Internal/HTTP.hs
@@ -12,7 +12,8 @@
        ( Manager,
          OurHttpException,
          niceHTTPManager,
-         fetchURL
+         fetchURL,
+         asStatusFailureException
        ) where
 
 import Control.Applicative ((<$>))
@@ -55,3 +56,10 @@
     else return ()
   rethrower :: H.HttpException -> IO a
   rethrower e = throwIO $ OtherHttpException e
+
+asStatusFailureException :: OurHttpException
+                         -> Maybe Int -- ^ HTTP status code
+asStatusFailureException (StatusFailureException _ res) = Just code
+  where
+    code = fromEnum $ H.responseStatus res
+asStatusFailureException _ = Nothing
diff --git a/src/Staversion/Internal/Query.hs b/src/Staversion/Internal/Query.hs
--- a/src/Staversion/Internal/Query.hs
+++ b/src/Staversion/Internal/Query.hs
@@ -25,6 +25,12 @@
 -- | Source of packages.
 data PackageSource = SourceStackage Resolver -- ^ stackage.
                    | SourceHackage -- ^ hackage (latest)
+                   | SourceStackYaml FilePath
+                     -- ^ stack.yaml file. Its \"resolver\" field is
+                     -- used as the package source.
+                   | SourceStackDefault
+                     -- ^ the resolver that the @stack@ command would
+                     -- use by default.
                    deriving (Show,Eq,Ord)
 
 -- | Query for package version(s).
@@ -38,6 +44,8 @@
 sourceDesc :: PackageSource -> Text
 sourceDesc (SourceStackage r) = pack r
 sourceDesc SourceHackage = "latest in hackage"
+sourceDesc (SourceStackYaml p) = pack p
+sourceDesc SourceStackDefault = "default stack resolver"
 
 parseQuery :: String -> Query
 parseQuery s = if ".cabal" `isSuffixOf` s
diff --git a/staversion.cabal b/staversion.cabal
--- a/staversion.cabal
+++ b/staversion.cabal
@@ -1,5 +1,5 @@
 name:                   staversion
-version:                0.2.1.4
+version:                0.2.2.0
 author:                 Toshio Ito <debug.ito@gmail.com>
 maintainer:             Toshio Ito <debug.ito@gmail.com>
 license:                BSD3
@@ -20,7 +20,8 @@
                         test/data/doctest.cabal_test,
                         test/data/conduit.cabal_test,
                         test/data/foobar.cabal_test,
-                        test/data/braces.cabal_test
+                        test/data/braces.cabal_test,
+                        test/data/stack_sample.yaml
                         
 homepage:               https://github.com/debug-ito/staversion
 bug-reports:            https://github.com/debug-ito/staversion/issues
@@ -33,6 +34,7 @@
   other-extensions:     CPP, DeriveDataTypeable, TupleSections
   exposed-modules:      Staversion.Internal.BuildPlan,
                         Staversion.Internal.BuildPlan.Stackage,
+                        Staversion.Internal.BuildPlan.StackYaml,
                         Staversion.Internal.BuildPlan.Hackage,
                         Staversion.Internal.BuildPlan.Version,
                         Staversion.Internal.Query,
@@ -49,7 +51,7 @@
                         Staversion.Internal.Megaparsec
   build-depends:        base >=4.8 && <4.12,
                         unordered-containers >=0.2.3 && <0.3,
-                        aeson >=0.8.0 && <1.4,
+                        aeson >=0.8.0 && <1.5,
                         text >=0.11.3 && <1.3,
                         bytestring >=0.10.0 && <0.11,
                         yaml >=0.8.3 && <0.9,
@@ -62,11 +64,12 @@
                         http-types >=0.8.6 && <0.13,
                         transformers >=0.3.0 && <0.6,
                         transformers-compat >=0.4.0 && <0.7,
-                        megaparsec >=4.2.0 && <6.5,
+                        megaparsec >=4.2.0 && <6.6,
                         semigroups >=0.18.0.1 && <0.19,
                         Cabal >=1.22.6.0 && <2.3,
                         pretty >=1.1.2.0 && <1.2,
-                        ansi-wl-pprint >=0.6.7.3 && <0.7
+                        ansi-wl-pprint >=0.6.7.3 && <0.7,
+                        process >=1.2.3.0 && <1.7
 
 executable staversion
   default-language:     Haskell2010
@@ -84,21 +87,24 @@
   hs-source-dirs:       test
   ghc-options:          -Wall -fno-warn-unused-imports -fno-warn-orphans "-with-rtsopts=-M512m"
   main-is:              Spec.hs
-  default-extensions:   OverloadedStrings
+  default-extensions:   OverloadedStrings, QuasiQuotes
   -- other-extensions:     
   other-modules:        Staversion.Internal.BuildPlanSpec,
                         Staversion.Internal.BuildPlan.StackageSpec,
                         Staversion.Internal.BuildPlan.HackageSpec,
                         Staversion.Internal.BuildPlan.VersionSpec,
+                        Staversion.Internal.BuildPlan.StackYamlSpec,
                         Staversion.Internal.ExecSpec,
                         Staversion.Internal.FormatSpec,
                         Staversion.Internal.CabalSpec,
                         Staversion.Internal.AggregateSpec,
+                        Staversion.Internal.CommandSpec,
                         Staversion.Internal.TestUtil
   build-depends:        base, staversion, text, filepath, bytestring,
                         Cabal, semigroups,
                         hspec >=2.1.7,
-                        QuickCheck >=2.8.1 && <2.12
+                        QuickCheck >=2.8.1 && <2.12,
+                        heredoc >=0.2.0.0 && <0.3
 
 flag network-test
   description: Enable network tests.
diff --git a/test/Staversion/Internal/BuildPlan/StackYamlSpec.hs b/test/Staversion/Internal/BuildPlan/StackYamlSpec.hs
new file mode 100644
--- /dev/null
+++ b/test/Staversion/Internal/BuildPlan/StackYamlSpec.hs
@@ -0,0 +1,42 @@
+{-# LANGUAGE QuasiQuotes, OverloadedStrings #-}
+module Staversion.Internal.BuildPlan.StackYamlSpec (main,spec) where
+
+import Data.Text (Text)
+import Test.Hspec
+import Text.Heredoc (here)
+
+import Staversion.Internal.BuildPlan.StackYaml (configLocationFromText)
+
+main :: IO ()
+main = hspec spec
+
+spec :: Spec
+spec = describe "configLocationFromText" $ do
+  it "should load config-location field" $ do
+    configLocationFromText sample `shouldBe` Right "/home/debugito/programs/git/staversion/stack.yaml"
+
+sample :: Text
+sample = [here|stack-root: /home/debugito/.stack
+project-root: /home/debugito/programs/git/staversion
+config-location: /home/debugito/programs/git/staversion/stack.yaml
+bin-path: /home/debugito/.stack/snapshots/x86_64-linux/lts-10.8/8.2.2/bin:/home/debugito/.stack/compiler-tools/x86_64-linux/ghc-8.2.2/bin:/home/debugito/.stack/programs/x86_64-linux/ghc-8.2.2/bin:/home/debugito/.plenv/shims:/home/debugito/.plenv/bin:/opt/gradle/bin:/home/debugito/.local/bin:/home/debugito/gems/bin:/home/debugito/perl5/bin:/home/debugito/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
+programs: /home/debugito/.stack/programs/x86_64-linux
+compiler-exe: /home/debugito/.stack/programs/x86_64-linux/ghc-8.2.2/bin/ghc
+compiler-bin: /home/debugito/.stack/programs/x86_64-linux/ghc-8.2.2/bin
+compiler-tools-bin: /home/debugito/.stack/compiler-tools/x86_64-linux/ghc-8.2.2/bin
+local-bin: /home/debugito/.local/bin
+extra-include-dirs: 
+extra-library-dirs: 
+snapshot-pkg-db: /home/debugito/.stack/snapshots/x86_64-linux/lts-10.8/8.2.2/pkgdb
+local-pkg-db: /home/debugito/programs/git/staversion/.stack-work/install/x86_64-linux/lts-10.8/8.2.2/pkgdb
+global-pkg-db: /home/debugito/.stack/programs/x86_64-linux/ghc-8.2.2/lib/ghc-8.2.2/package.conf.d
+ghc-package-path: /home/debugito/programs/git/staversion/.stack-work/install/x86_64-linux/lts-10.8/8.2.2/pkgdb:/home/debugito/.stack/snapshots/x86_64-linux/lts-10.8/8.2.2/pkgdb:/home/debugito/.stack/programs/x86_64-linux/ghc-8.2.2/lib/ghc-8.2.2/package.conf.d
+snapshot-install-root: /home/debugito/.stack/snapshots/x86_64-linux/lts-10.8/8.2.2
+local-install-root: /home/debugito/programs/git/staversion/.stack-work/install/x86_64-linux/lts-10.8/8.2.2
+snapshot-doc-root: /home/debugito/.stack/snapshots/x86_64-linux/lts-10.8/8.2.2/doc
+local-doc-root: /home/debugito/programs/git/staversion/.stack-work/install/x86_64-linux/lts-10.8/8.2.2/doc
+dist-dir: .stack-work/dist/x86_64-linux/Cabal-2.0.1.0
+local-hpc-root: /home/debugito/programs/git/staversion/.stack-work/install/x86_64-linux/lts-10.8/8.2.2/hpc
+local-bin-path: /home/debugito/.local/bin
+ghc-paths: /home/debugito/.stack/programs/x86_64-linux
+|]
diff --git a/test/Staversion/Internal/BuildPlanSpec.hs b/test/Staversion/Internal/BuildPlanSpec.hs
--- a/test/Staversion/Internal/BuildPlanSpec.hs
+++ b/test/Staversion/Internal/BuildPlanSpec.hs
@@ -70,8 +70,14 @@
 
 loadBuildPlan_spec :: Spec
 loadBuildPlan_spec = describe "loadBuildPlan" $ do
+  let expRight = either (\e -> error ("Error: " ++ e)) return
   it "reads local file after disambiguation" $ do
     bp_man <- mockBuildPlanManager 4 2
-    bp <- either (\e -> error ("Error: " ++ e)) return =<< loadBuildPlan bp_man [] (SourceStackage "lts")
+    bp <- expRight =<< loadBuildPlan bp_man [] (SourceStackage "lts")
     packageVersion bp "base" `shouldBe` (Just $ ver [4,8,2,0])
+    buildPlanSource bp `shouldBe` SourceStackage "lts-4.2"
+  it "reads the given stack.yaml for resolver" $ do
+    bp_man <- mockBuildPlanManager 4 2
+    bp <- expRight =<< loadBuildPlan bp_man [] (SourceStackYaml ("test" </> "data" </> "stack_sample.yaml"))
+    packageVersion bp "optparse-applicative" `shouldBe` (Just $ ver [0,12,0,0])
     buildPlanSource bp `shouldBe` SourceStackage "lts-4.2"
diff --git a/test/Staversion/Internal/CommandSpec.hs b/test/Staversion/Internal/CommandSpec.hs
new file mode 100644
--- /dev/null
+++ b/test/Staversion/Internal/CommandSpec.hs
@@ -0,0 +1,25 @@
+{-# LANGUAGE OverloadedStrings #-}
+module Staversion.Internal.CommandSpec (main,spec) where
+
+import Test.Hspec
+
+import Staversion.Internal.Command
+  ( _parseCommandStrings, Command(..)
+  )
+import Staversion.Internal.Query
+  ( PackageSource(..), Query(..)
+  )
+
+main :: IO ()
+main = hspec spec
+
+spec :: Spec
+spec = describe "_parseCommandStrings" $ do
+  it "should use SourceStackDefault if no source is specified." $ do
+    (Just com) <- _parseCommandStrings ["aeson"]
+    commQueries com `shouldBe` [QueryName "aeson"]
+    commSources com `shouldBe` [SourceStackDefault]
+  it "should use the given sources when there are some." $ do
+    (Just com) <- _parseCommandStrings ["-r", "lts-10", "base"]
+    commQueries com `shouldBe` [QueryName "base"]
+    commSources com `shouldBe` [SourceStackage "lts-10"]
diff --git a/test/Staversion/Internal/ExecSpec.hs b/test/Staversion/Internal/ExecSpec.hs
--- a/test/Staversion/Internal/ExecSpec.hs
+++ b/test/Staversion/Internal/ExecSpec.hs
@@ -136,7 +136,8 @@
                         commQueries = [],
                         commAllowNetwork = False,
                         commAggregator = Nothing,
-                        commFormatConfig = defFormatConfig
+                        commFormatConfig = defFormatConfig,
+                        commStackCommand = "stack"
                       }
 
 spec_processCommand_disambiguates :: Spec
diff --git a/test/data/stack_sample.yaml b/test/data/stack_sample.yaml
new file mode 100644
--- /dev/null
+++ b/test/data/stack_sample.yaml
@@ -0,0 +1,77 @@
+# This file was automatically generated by 'stack init'
+#
+# Some commonly used options have been documented as comments in this file.
+# For advanced use and comprehensive documentation of the format, please see:
+# https://docs.haskellstack.org/en/stable/yaml_configuration/
+
+# Resolver to choose a 'specific' stackage snapshot or a compiler version.
+# A snapshot resolver dictates the compiler version and the set of packages
+# to be used for project dependencies. For example:
+#
+# resolver: lts-3.5
+# resolver: nightly-2015-09-21
+# resolver: ghc-7.10.2
+# resolver: ghcjs-0.1.0_ghc-7.10.2
+# resolver:
+#  name: custom-snapshot
+#  location: "./custom-snapshot.yaml"
+resolver: lts-4.2
+
+# User packages to be built.
+# Various formats can be used as shown in the example below.
+#
+# packages:
+# - some-directory
+# - https://example.com/foo/bar/baz-0.0.2.tar.gz
+# - location:
+#    git: https://github.com/commercialhaskell/stack.git
+#    commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+# - location: https://github.com/commercialhaskell/stack/commit/e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#   extra-dep: true
+#  subdirs:
+#  - auto-update
+#  - wai
+#
+# A package marked 'extra-dep: true' will only be built if demanded by a
+# non-dependency (i.e. a user package), and its test suites and benchmarks
+# will not be run. This is useful for tweaking upstream packages.
+packages:
+- .
+
+# Dependency packages to be pulled from upstream that are not in the resolver
+# (e.g., acme-missiles-0.3)
+extra-deps: []
+
+#### confirmed on 2018-03-12
+## - aeson-1.3.0.0
+## - QuickCheck-2.11.3
+## - doctest-0.14.1
+## - text-1.2.3.0
+## - hspec-core-2.4.8
+## - hspec-2.4.8
+## - hspec-discover-2.4.8
+## - hspec-expectations-0.8.2
+
+# Override default flag values for local packages and extra-deps
+flags: {}
+
+# Extra package databases containing global packages
+extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+#
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: ">=1.5"
+#
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+#
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+#
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor