Update proxy to pass query-string

HTTP proxy was not passing query-string upstream. This change
reinstates the behaviour through TDD - adding test coverage and
automated regression testing.

Signed-off-by: Alex Ellis (VMware) <alexellis2@gmail.com>

gateway/handlers/forwarding_proxy_test.go

@@ -0,0 +1,68 @@
+package handlers
+
+import (
+	"bytes"
+	"io/ioutil"
+	"net/http"
+	"testing"
+)
+
+func Test_buildUpstreamRequest_Body_Method_Query(t *testing.T) {
+	srcBytes := []byte("hello world")
+
+	reader := bytes.NewReader(srcBytes)
+	request, _ := http.NewRequest(http.MethodPost, "/?code=1", reader)
+	request.Header.Set("X-Source", "unit-test")
+
+	if request.URL.RawQuery != "code=1" {
+		t.Errorf("Query - want: %s, got: %s", "code=1", request.URL.RawQuery)
+		t.Fail()
+	}
+
+	upstream := buildUpstreamRequest(request, "/")
+
+	if request.Method != upstream.Method {
+		t.Errorf("Method - want: %s, got: %s", request.Method, upstream.Method)
+		t.Fail()
+	}
+
+	upstreamBytes, _ := ioutil.ReadAll(upstream.Body)
+
+	if string(upstreamBytes) != string(srcBytes) {
+		t.Errorf("Body - want: %s, got: %s", string(upstreamBytes), string(srcBytes))
+		t.Fail()
+	}
+
+	if request.Header.Get("X-Source") != upstream.Header.Get("X-Source") {
+		t.Errorf("Header X-Source - want: %s, got: %s", request.Header.Get("X-Source"), upstream.Header.Get("X-Source"))
+		t.Fail()
+	}
+
+	if request.URL.RawQuery != upstream.URL.RawQuery {
+		t.Errorf("URL.RawQuery - want: %s, got: %s", request.URL.RawQuery, upstream.URL.RawQuery)
+		t.Fail()
+	}
+
+}
+
+func Test_buildUpstreamRequest_NoBody_GetMethod_NoQuery(t *testing.T) {
+	request, _ := http.NewRequest(http.MethodGet, "/", nil)
+
+	upstream := buildUpstreamRequest(request, "/")
+
+	if request.Method != upstream.Method {
+		t.Errorf("Method - want: %s, got: %s", request.Method, upstream.Method)
+		t.Fail()
+	}
+
+	if upstream.Body != nil {
+		t.Errorf("Body - expected nil")
+		t.Fail()
+	}
+
+	if request.URL.RawQuery != upstream.URL.RawQuery {
+		t.Errorf("URL.RawQuery - want: %s, got: %s", request.URL.RawQuery, upstream.URL.RawQuery)
+		t.Fail()
+	}
+
+}