*: use go install instead of go build in build script

go-sqlite3 takes a long time to compile, so it's very important
to cache a build rather than re-compile every time.

Use go install instead of go build in the build script to cache
all packages. Print a warning in the test script if cached packages
are not found.

build

@@ -1,18 +1,10 @@
 #!/bin/bash -e
 
-export GOPATH=${PWD}/Godeps/_workspace
-export GOBIN=${PWD}/bin
+source ./env
 
-rm -rf $GOPATH/src/github.com/coreos/dex
-mkdir -p $GOPATH/src/github.com/coreos/
-
-# Only attempt to link dex into godeps if it isn't already there
-[ -d $GOPATH/src/github.com/coreos/dex ] || ln -s ${PWD} $GOPATH/src/github.com/coreos/dex
-
-LD_FLAGS="-X main.version=$(./git-version)"
-go build -o bin/dex-worker -ldflags="$LD_FLAGS" github.com/coreos/dex/cmd/dex-worker
-go build -o bin/dexctl -ldflags="$LD_FLAGS" github.com/coreos/dex/cmd/dexctl
-go build -o bin/dex-overlord -ldflags="$LD_FLAGS" github.com/coreos/dex/cmd/dex-overlord
+go install -ldflags="$LD_FLAGS" github.com/coreos/dex/cmd/dex-worker
+go install -ldflags="$LD_FLAGS" github.com/coreos/dex/cmd/dexctl
+go install -ldflags="$LD_FLAGS" github.com/coreos/dex/cmd/dex-overlord
 go build -o bin/example-app github.com/coreos/dex/examples/app
 go build -o bin/example-cli github.com/coreos/dex/examples/cli
-go build -o bin/gendoc github.com/coreos/dex/cmd/gendoc
+go install github.com/coreos/dex/cmd/gendoc

env

@@ -0,0 +1,10 @@
+export GOPATH=${PWD}/Godeps/_workspace
+export GOBIN=${PWD}/bin
+
+rm -rf $GOPATH/src/github.com/coreos/dex
+mkdir -p $GOPATH/src/github.com/coreos/
+
+# Only attempt to link dex into godeps if it isn't already there
+[ -d $GOPATH/src/github.com/coreos/dex ] || ln -s ${PWD} $GOPATH/src/github.com/coreos/dex
+
+LD_FLAGS="-X main.version=$(./git-version)"

test

@@ -12,7 +12,11 @@
 # Invoke ./cover for HTML output
 COVER=${COVER:-"-cover"}
 
-source ./build
+source ./env
+
+if [ ! -d $GOPATH/pkg ]; then
+	echo "WARNING: No cached builds detected. Please run the ./build script to speed up future tests."
+fi
 
 TESTABLE="connector db integration pkg/crypto pkg/flag pkg/http pkg/net pkg/time pkg/html functional/repo server session session/manager user user/api user/manager user/email email admin"
 FORMATTABLE="$TESTABLE cmd/dexctl cmd/dex-worker cmd/dex-overlord examples/app functional pkg/log"

test-functional

@@ -1,4 +1,6 @@
 #!/bin/bash -e
-source ./build
+
+source ./env
+
 go test $@ github.com/coreos/dex/functional
 go test $@ github.com/coreos/dex/functional/repo