diff --git a/google/internal/oauth/stsExchange_test.go b/google/internal/oauth/stsExchange_test.go
index 99f8959..a8cd4a3 100644
--- a/google/internal/oauth/stsExchange_test.go
+++ b/google/internal/oauth/stsExchange_test.go
@@ -1,11 +1,12 @@
 package externalaccount
 
 import (
-"github.com/google/go-cmp/cmp"
-"golang.org/x/oauth2"
-"net/http"
-"net/http/httptest"
-"testing"
+	"github.com/google/go-cmp"
+	"golang.org/x/oauth2"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"testing"
 )
 
 var auth = ClientAuthentication{
@@ -24,80 +25,56 @@ var tokenRequest = STSTokenExchangeRequest{
 	Audience:           "32555940559.apps.googleusercontent.com",  //TODO: Make sure audience is correct in this test (might be mismatched)
 	Scope:              []string{"https://www.googleapis.com/auth/devstorage.full_control"},
 	RequestedTokenType: "urn:ietf:params:oauth:token-type:access_token",
-	SubjectToken:       "eyJhbGciOiJSUzI1NiIsImtpZCI6IjJjNmZhNmY1OTUwYTdjZTQ2NWZjZjI0N2FhMGIwOTQ4MjhhYzk1MmMiLCJ0eXAiOiJKV1QifQ.eyJpc3MiOiJodHRwczovL2FjY291bnRzLmdvb2dsZS5jb20iLCJhenAiOiIzMjU1NTk0MDU1OS5hcHBzLmdvb2dsZXVzZXJjb250ZW50LmNvbSIsImF1ZCI6IjMyNTU1OTQwNTU5LmFwcHMuZ29vZ2xldXNlcmNvbnRlbnQuY29tIiwic3ViIjoiMTEzMzE4NTQxMDA5MDU3Mzc4MzI4IiwiaGQiOiJnb29nbGUuY29tIiwiZW1haWwiOiJpdGh1cmllbEBnb29nbGUuY29tIiwiZW1haWxfdmVyaWZpZWQiOnRydWUsImF0X2hhc2giOiJyWUtBTjZwX21rS0U4U2ItN3ZGalBBIiwiaWF0IjoxNjAxNTk0NDY1LCJleHAiOjE2MDE1OTgwNjV9.mWOLjD6ghfgrFNcm_1h-wrpLlKFc2WSS13lu2L5t4549uYhX5DEbI7MmeUEwXSffrns1ljcdbJm4nXymXK3AH6ftRV17O3BnOsWngxKj5eKhzOMF308YNXjBKTDiu_crzjCpf_2ng03IIGbFsTvAUx4wvWhnFO-z4xl2tb13OMCxpkw52dO1ZcFhw0d_1iUj_q0UL9E15ADL4SOr-BVtXerWPhNVBplTw8gzL4HHmo2GGUA_ilQpJzD528BKLygemqy1taXZwOGJEAUYkcKm8DhA0NJWneUyqHN6qbs0wm_d_nZsiFx9CIDblt1dUkgfuPIsno-xrkkkwubcv1WlgA",
+	SubjectToken:       "eyJhbGciOiJSUzI1NiIsImtpIjJjNmZhNmY1OTUwYTdjZTQ2NWZjZjI0N2FhMGIwOTQ4MjhhYzk1MmMiLCJ0eXAiOiJKV1QifQ.eyJpc3MiOiJodHRwczovL2FjY291bnRzLmdvb2dsZS5jb20iLCJhenAiOiIzMjU1NTk0MDU1OS5hcHBzLmdvb2dsZXVzZXJjb250ZW50LmNvbSIsImF1IjMyNTU1OTQwNTU5LmFwcHMuZ29vZ2xldXNlcmNvbnRlbnQuY29tIiwic3ViIjoiMTEzMzE4NTQxMDA5MDU3Mzc4MzI4IiwiaGQiOiJnb29nbGUuY29tIiwiZW1haWwiOiJpdGh1cmllbEBnb29nbGUuY29tIiwiZW1haWxfdmVyaWZpZWQiOnRydWUsImF0X2hhc2giOiJyWUtBTjZwX21rS0U4U2ItN3ZGalBBIiwiaWF0IjoxNjAxNTk0NDY1LCJleHAiOjE2MDE1OTgwNjV9.mWOLjD6ghfgrFNcm_1h-wrpLlKFc2WSS13lu2L5t4549uYhX5DEbI7MmeUEwXSffrns1ljcdbJm4nXymXK3AH6ftRV17O3BnOsWngxKj5eKhzOMF308YNXjBKTDiu_crzjCpf_2ng03IIGbFsTvAUx4wvWhnFO-z4xl2tb13OMCxpkw52dO1ZcFhw0d_1iUj_q0UL9E15ADL4SOr-BVtXerWPhNVBplTw8gzL4HHmo2GGUA_ilQpJzD528BKLygemqy1taXZwOGJEAUYkcKm8DhA0NJWneUyqHN6qbs0wm_d_nZsiFx9CIDblt1dUkgfuPIsno-xrkkkwubcv1WlgA",
 	SubjectTokenType:   "urn:ietf:params:oauth:token-type:jwt",
 }
 
-var serverReq = http.Request{
-	Method:           "POSTURL:/",
-	URL:              nil,
-	Proto:            "HTTP/1.1",
-	ProtoMajor:       1,
-	ProtoMinor:       1,
-	Header:           map[string][]string{
-		"Accept-Encoding": []string{"gzip"},
-		"Authorization": []string{"Basic cmJyZ25vZ25yaG9uZ28zYmk0Z2I5Z2hnOWc6bm90c29zZWNyZXQ="},
-		"Content-Length": []string{"1192"},
-		"Content-Type": []string{"application/x-www-form-urlencoded"},
-		"User-Agent": []string{"Go-http-client/1.1"},
-	},
-	Body:             nil, //TODO: Construct this struct
-	ContentLength:    1192,
-	Close:            false,
-	Host:             "127.0.0.1:41147", //TODO: Does this conflict due to separate addresses?
-	Form:             nil,  //TODO: Should Form, PostForm, TransferEncoding, etc be initialized with Make?
-	PostForm:         nil,
-	MultipartForm:    nil,
-	Trailer:          nil,
-	RemoteAddr:       "127.0.0.1:52760",
-	RequestURI:       "/",
-	TLS:              nil,
-	Cancel:           nil,
-	Response:         nil,
-}
-
-var serverResp = http.Response{
-	Status:           "200 OK",
-	StatusCode:       200,
-	Proto:            "HTTP/1.1",
-	ProtoMajor:       1,
-	ProtoMinor:       1,
-	Header:           map[string][]string{
-		"Connection":[]string{"keep-alive"},
-		"Content-Length":[]string{"362"},
-		"Content-Type":[]string{"application/json; charset=utf-8"},
-		"Date":[]string{"Wed, 07 Oct 2020 21:54:27 GMT"},
-		"X-Powered-By":[]string{"Express"},
-	},
-	Body:             nil,
-	ContentLength:    0,
-	TransferEncoding: nil,
-	Close:            false,
-	Uncompressed:     false,
-	Trailer:          nil,
-	Request:          nil,
-	TLS:              nil,
+var requestbody = "audience=32555940559.apps.googleusercontent.com&grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Atoken-exchange&requested_token_type=urn%3Aietf%3Aparams%3Aoauth%3Atoken-type%3Aaccess_token&scope=https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fdevstorage.full_control&subject_token=eyJhbGciOiJSUzI1NiIsImtpIjJjNmZhNmY1OTUwYTdjZTQ2NWZjZjI0N2FhMGIwOTQ4MjhhYzk1MmMiLCJ0eXAiOiJKV1QifQ.eyJpc3MiOiJodHRwczovL2FjY291bnRzLmdvb2dsZS5jb20iLCJhenAiOiIzMjU1NTk0MDU1OS5hcHBzLmdvb2dsZXVzZXJjb250ZW50LmNvbSIsImF1IjMyNTU1OTQwNTU5LmFwcHMuZ29vZ2xldXNlcmNvbnRlbnQuY29tIiwic3ViIjoiMTEzMzE4NTQxMDA5MDU3Mzc4MzI4IiwiaGQiOiJnb29nbGUuY29tIiwiZW1haWwiOiJpdGh1cmllbEBnb29nbGUuY29tIiwiZW1haWxfdmVyaWZpZWQiOnRydWUsImF0X2hhc2giOiJyWUtBTjZwX21rS0U4U2ItN3ZGalBBIiwiaWF0IjoxNjAxNTk0NDY1LCJleHAiOjE2MDE1OTgwNjV9.mWOLjD6ghfgrFNcm_1h-wrpLlKFc2WSS13lu2L5t4549uYhX5DEbI7MmeUEwXSffrns1ljcdbJm4nXymXK3AH6ftRV17O3BnOsWngxKj5eKhzOMF308YNXjBKTDiu_crzjCpf_2ng03IIGbFsTvAUx4wvWhnFO-z4xl2tb13OMCxpkw52dO1ZcFhw0d_1iUj_q0UL9E15ADL4SOr-BVtXerWPhNVBplTw8gzL4HHmo2GGUA_ilQpJzD528BKLygemqy1taXZwOGJEAUYkcKm8DhA0NJWneUyqHN6qbs0wm_d_nZsiFx9CIDblt1dUkgfuPIsno-xrkkkwubcv1WlgA&subject_token_type=urn%3Aietf%3Aparams%3Aoauth%3Atoken-type%3Ajwt"
+var responseBody = `{"access_token":"ya29.a0AfH6SMCqKiKaHEpqs9sl6cocVlqG2dvP2g7eURqGNCfUyKZ6lYSHz531aioS3_0w_xdNDfj6A-Hzk6-0-M6olf3O-zfcGFd678lVuvplpclaK4XQ4ete6_9xSUFU08RefwE53rf2OW8FOQvjpQB-PmPhHZTzK99YYHNtjas","issued_token_type":"urn:ietf:params:oauth:token-type:access_token","token_type":"Bearer","expires_in":3600,"scope":"https://www.googleapis.com/auth/cloud-platform"}`
+var expectedToken = STSTokenExchangeResponse{
+	AccessToken: "ya29.a0AfH6SMCqKiKaHEpqs9sl6cocVlqG2dvP2g7eURqGNCfUyKZ6lYSHz531aioS3_0w_xdNDfj6A-Hzk6-0-M6olf3O-zfcGFd678lVuvplpclaK4XQ4ete6_9xSUFU08RefwE53rf2OW8FOQvjpQB-PmPhHZTzK99YYHNtjas",
+	IssuedTokenType: "urn:ietf:params:oauth:token-type:access_token",
+	TokenType: "Bearer",
+	ExpiresIn: 3600,
+	Scope: "https://www.googleapis.com/auth/cloud-platform",
+	RefreshToken: "",
 }
 
 func TestExchangeToken(t *testing.T) {
 
-
-
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		if diff := cmp.Diff(*r, serverReq); diff != "" {
-			t.Errorf("mismatched messages received by mock server (-want +got): \n%s", diff)
+		if r.URL.String() != "/" {
+			t.Errorf("Unexpected request URL, %v is found.", r.URL)
 		}
-		if r.URL.String() !=
-
-		return
+		headerAuth := r.Header.Get("Authorization")
+		if headerAuth != "Basic cmJyZ25vZ25yaG9uZ28zYmk0Z2I5Z2hnOWc6bm90c29zZWNyZXQ=" {
+			t.Errorf("Unexpected autohrization header, %v is found.", headerAuth)
+		}
+		headerContentType := r.Header.Get("Content-Type")
+		if headerContentType != "application/x-www-form-urlencoded]" {
+			t.Errorf("Unexpected Content-Type header, %v is found.", headerContentType)
+		}
+		body, err := ioutil.ReadAll(r.Body)
+		if err != nil {
+			t.Errorf("Failed reading request body: %s.", err)
+		}
+		if string(body) != requestbody {
+			t.Errorf("Unexpected exchange payload, %v is found.", string(body))
+		}
+		w.Header().Set("Content-Type", "application/json")
+		w.Write([]byte(responseBody))
 	}))
 
 	headers := make(map[string][]string)
 	headers["Content-Type"] = []string{"application/x-www-form-urlencoded"}
 
-	//TODO: Call TokenExchange, make sure I get the right results
 	resp, err := ExchangeToken(ts.URL, &tokenRequest, auth, headers, nil)
 	if err != nil {
 		t.Errorf("ExchangeToken failed with error: %s", err)
 	}
+
+	if diff := cmp.Diff(resp, expectedToken); diff != "" {
+		t.Errorf("mismatched messages received by mock server (-want +got): \n%v", diff)
+	}
+
 }
\ No newline at end of file