server: speed up unit test (pingcap#2010)

run many test cases parallel
split databases in server package for parallel

_vendor/src/github.com/pingcap/check/check.go

@@ -86,6 +86,7 @@ type C struct {
 	logb      *logger
 	logw      io.Writer
 	done      chan *C
+	parallel  chan *C
 	reason    string
 	mustFail  bool
 	tempDir   *tempDir
@@ -611,13 +612,23 @@ func (runner *suiteRunner) run() *Result {
 		if runner.checkFixtureArgs() {
 			c := runner.runFixture(runner.setUpSuite, "", nil)
 			if c == nil || c.status() == succeededSt {
+				var delayedC []*C
 				for i := 0; i != len(runner.tests); i++ {
-					c := runner.runTest(runner.tests[i])
+					c := runner.forkTest(runner.tests[i])
+					select {
+					case <-c.done:
+					case <-c.parallel:
+						delayedC = append(delayedC, c)
+					}
 					if c.status() == fixturePanickedSt {
 						runner.skipTests(missedSt, runner.tests[i+1:])
 						break
 					}
 				}
+				// Wait those parallel tests finish.
+				for _, delayed := range delayedC {
+					<-delayed.done
+				}
 			} else if c != nil && c.status() == skippedSt {
 				runner.skipTests(skippedSt, runner.tests)
 			} else {
@@ -655,6 +666,7 @@ func (runner *suiteRunner) forkCall(method *methodType, kind funcKind, testName
 		logw:      logw,
 		tempDir:   runner.tempDir,
 		done:      make(chan *C, 1),
+		parallel:  make(chan *C, 1),
 		timer:     timer{benchTime: runner.benchTime},
 		startTime: time.Now(),
 		benchMem:  runner.benchMem,

_vendor/src/github.com/pingcap/check/helpers.go

@@ -76,6 +76,11 @@ func (c *C) Skip(reason string) {
 	c.stopNow()
 }
 
+// Parallel will mark the test run parallel within a test suite.
+func (c *C) Parallel() {
+	c.parallel <- c
+}
+
 // -----------------------------------------------------------------------
 // Basic logging.