travis: staged travis builds

This PR introduces staging to our travis pipeline. Currently all
instances perform:

 - compilation of lnd
 - linting
 - compilation and installation of btcd binaries
 - installation of bitcoind binaries

In total this adds about 3 minutes to each of our 5 instances, resulting in
roughly 12 minutes of redundant execution time. Additionally, if if a build
fails to compile or lint we detect this 5 separate times, consuming precious
instances from other builds.

We alleviate this by adding an initial Build phase, which runs a single
instance performing the actions above. This has the benefit of quickly sanity
checking the pr before moving on to the more expensive unit or integration test
suites, and failing faster for common mistakes. It also warms up the build
caches for the Test stage in one fell swoop.

For instance, if 5 people push changes at the same time, they can all get
immediate feedback regarding compilation or linting issues, and potentially
save hours waiting for other people's test to finish or fail before finding out
they had a spelling error. This doesn't alleviate all possible issues, e.g. the
5 instances may already be consumed by test suites, but it does make a sizable
step towards minimizing time-to-failure in common scenarios.

.travis.yml

@@ -14,33 +14,29 @@ go:
 env:
   global:
     - GOCACHE=$HOME/.go-build
-  matrix:
-    - RACE=true
-    - ITEST=true
-    - NEUTRINO_ITEST=true
-    - BITCOIND_ITEST=true
-    - COVER=true 
 
 sudo: required
 
-script:
-  - export GO111MODULE=on
-  - bash ./scripts/install_bitcoind.sh
+before_script: bash ./scripts/install_bitcoind.sh
 
-  # Run unit tests with race condition detector.
-  - 'if [ "$RACE" = true ]; then make travis-race ; fi'
-
-  # Run btcd integration tests.
-  - 'if [ "$ITEST" = true ]; then make travis-itest; fi'
-
-  # Run neutrino integration tests.
-  - 'if [ "$NEUTRINO_ITEST" = true ]; then make travis-itest backend=neutrino; fi'
-
-  # Run bitcoind integration tests.
-  - 'if [ "$BITCOIND_ITEST" = true ]; then make travis-itest backend=bitcoind; fi'
-
-  # Run unit tests and generate coverage report.
-  - 'if [ "$COVER" = true ]; then make travis-cover; fi'
+jobs:
+  include:
+    - stage: Build
+      script: 
+      - make unit pkg=... case=_NONE_ 
+      - make lint
+      - make btcd
+    - stage: Test
+      script: make travis-cover
+      name: Unit Cover
+    - script: make travis-race
+      name: Unit Race
+    - script: make itest
+      name: Btcd Integration
+    - script: make itest backend=bitcoind
+      name: Bitcoind Integration
+    - script: make itest backend=neutrino
+      name: Neutrino Integration
 
 after_script:
   - LOG_FILES=./lntest/itest/*.log

Makefile

@@ -135,11 +135,9 @@ goveralls: $(GOVERALLS_BIN)
 	$(GOVERALLS_BIN) -coverprofile=coverage.txt -service=travis-ci
 
 
-travis-race: lint btcd unit-race
+travis-race: btcd unit-race
 
-travis-cover: lint btcd unit-cover goveralls
-
-travis-itest: lint itest
+travis-cover: btcd unit-cover goveralls
 
 # =============
 # FLAKE HUNTING