related: https://github.com/fnproject/fdk-go/pull/26 (#968)

adds a test for the protocol dumping of a request to the containert stdin.
there are a number of vectors to test for a cloud event, but since we're going
to change that behavior soon it's probably a waste of time to go about doing
so. in any event, this was pretty broken. my understanding of the cloud event
spec is deepening and the json stuff overall seems a little weird.

* fixes content type issue around json checking (since a string is also a json
value, we can just decode it, even though it's wasteful it's more easily
correct)
* doesn't force all json values to be map[string]interface{} and lets them be
whoever they want to be. maybe their dads are still proud.

closes #966

api/agent/protocol/cloudevent_test.go

@@ -0,0 +1,100 @@
+package protocol
+
+import (
+	"bytes"
+	"encoding/json"
+	"io"
+	"net/http"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/go-openapi/strfmt"
+)
+
+// implements CallInfo, modify as needed
+type testCall struct {
+	cloud       bool
+	contentType string
+	input       io.Reader
+}
+
+func (t *testCall) IsCloudEvent() bool  { return t.cloud }
+func (t *testCall) CallID() string      { return "foo" }
+func (t *testCall) ContentType() string { return t.contentType }
+func (t *testCall) Input() io.Reader    { return t.input }
+func (t *testCall) Deadline() strfmt.DateTime {
+	return strfmt.DateTime(time.Now().Add(30 * time.Second))
+}
+func (t *testCall) CallType() string             { return "sync" }
+func (t *testCall) ProtocolType() string         { return "http" }
+func (t *testCall) Request() *http.Request       { return nil } // unused here
+func (t *testCall) Method() string               { return "GET" }
+func (t *testCall) RequestURL() string           { return "http://example.com/r/yo/dawg" }
+func (t *testCall) Headers() map[string][]string { return map[string][]string{} }
+
+func TestJSONMap(t *testing.T) {
+	in := strings.NewReader(`{"yo":"dawg"}`)
+
+	var ib, ob bytes.Buffer
+	cep := &CloudEventProtocol{
+		in:  &ib,
+		out: &ob,
+	}
+
+	tc := &testCall{false, "application/json; charset=utf-8", in}
+
+	err := cep.writeJSONToContainer(tc)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var oce CloudEvent
+	err = json.NewDecoder(&ib).Decode(&oce)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	mappo, ok := oce.Data.(map[string]interface{})
+	if !ok {
+		t.Fatalf("data field should be map[string]interface{}: %T", oce.Data)
+	}
+
+	v, ok := mappo["yo"].(string)
+	if v != "dawg" {
+		t.Fatal("value in map is wrong", v)
+	}
+}
+
+func TestJSONNotMap(t *testing.T) {
+	// we accept all json values here https://tools.ietf.org/html/rfc7159#section-3
+	in := strings.NewReader(`true`)
+
+	var ib, ob bytes.Buffer
+	cep := &CloudEventProtocol{
+		in:  &ib,
+		out: &ob,
+	}
+
+	tc := &testCall{false, "application/json", in}
+
+	err := cep.writeJSONToContainer(tc)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var oce CloudEvent
+	err = json.NewDecoder(&ib).Decode(&oce)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	boolo, ok := oce.Data.(bool)
+	if !ok {
+		t.Fatalf("data field should be bool: %T", oce.Data)
+	}
+
+	if !boolo {
+		t.Fatal("bool should be true", boolo)
+	}
+}