Switch to ginkgo/gomega for tests

This switches over to ginkgo/gomega for tests, which makes writing
certain tests easier/more fluent in the future.

vendor/github.com/onsi/gomega/internal/testingtsupport/testing_t_support.go

@@ -0,0 +1,60 @@
+package testingtsupport
+
+import (
+	"regexp"
+	"runtime/debug"
+	"strings"
+
+	"github.com/onsi/gomega/types"
+)
+
+var StackTracePruneRE = regexp.MustCompile(`\/gomega\/|\/ginkgo\/|\/pkg\/testing\/|\/pkg\/runtime\/`)
+
+type EmptyTWithHelper struct{}
+
+func (e EmptyTWithHelper) Helper() {}
+
+type gomegaTestingT interface {
+	Fatalf(format string, args ...interface{})
+}
+
+func BuildTestingTGomegaFailWrapper(t gomegaTestingT) *types.GomegaFailWrapper {
+	tWithHelper, hasHelper := t.(types.TWithHelper)
+	if !hasHelper {
+		tWithHelper = EmptyTWithHelper{}
+	}
+
+	fail := func(message string, callerSkip ...int) {
+		if hasHelper {
+			tWithHelper.Helper()
+			t.Fatalf("\n%s", message)
+		} else {
+			skip := 2
+			if len(callerSkip) > 0 {
+				skip += callerSkip[0]
+			}
+			stackTrace := pruneStack(string(debug.Stack()), skip)
+			t.Fatalf("\n%s\n%s\n", stackTrace, message)
+		}
+	}
+
+	return &types.GomegaFailWrapper{
+		Fail:        fail,
+		TWithHelper: tWithHelper,
+	}
+}
+
+func pruneStack(fullStackTrace string, skip int) string {
+	stack := strings.Split(fullStackTrace, "\n")[1:]
+	if len(stack) > 2*skip {
+		stack = stack[2*skip:]
+	}
+	prunedStack := []string{}
+	for i := 0; i < len(stack)/2; i++ {
+		if !StackTracePruneRE.Match([]byte(stack[i*2])) {
+			prunedStack = append(prunedStack, stack[i*2])
+			prunedStack = append(prunedStack, stack[i*2+1])
+		}
+	}
+	return strings.Join(prunedStack, "\n")
+}