test(source/cloud-sql-mysql): create MCP integration tests by dishaprakash · Pull Request #2922 · googleapis/mcp-toolbox

dishaprakash · 2026-04-01T16:58:52Z

Description

This PR migrates the Cloud SQL MySQL integration tests to use the /mcp endpoint on the MCP Toolbox Server.

Key Changes

tests/mcp_tool.go:
- Added modular builder functions (Base, ExecuteSQL, TemplateParams) to dynamically generate expected MCP manifests.
- Added concatenation of individual MCP text blocks into a fully formatted JSON array whenever the test expects one, preserving compatibility with previous test assertions.
cloud_sql_mysql_mcp_test.go: Migrated legacy /api tests to /mcp
cloud_sql_mysql_create_instance_mcp_test.go: Migrated create-instance tests to validate MCP JSON-RPC handling.
tests/options.go: Added functional options for the various MySQL test fixtures to provide an MCP tests specific path
tests/tool.go: Used the above mentioned options to allow calling MCP Endpoints in the test fixtures of MySQL

gemini-code-assist

Code Review

This pull request introduces comprehensive integration tests for the Model Context Protocol (MCP) across various data sources, including AlloyDB, Cloud SQL MySQL, and HTTP. It also adds modular helper functions in tests/mcp_tool.go to facilitate standardized MCP tool testing. Several issues were identified in the review: a critical flaw in the Cloud SQL MySQL instance creation test where mocking http.DefaultClient fails to affect the separate toolbox process, and multiple violations of the repository style guide regarding tool naming conventions (snake_case and product name exclusion). Additionally, the use of time.Sleep in MySQL tests was flagged as a potential source of flakiness, and some error assertions were noted as being too weak.

tests/cloudsqlmysql/cloud_sql_mysql_create_instance_mcp_integration_test.go

tests/alloydb/alloydb_mcp_test.go

tests/cloudsqlmysql/cloud_sql_mysql_mcp_test.go

tests/mcp_tool.go

Yuan325 · 2026-04-09T21:52:30Z

tests/tool.go

+					errText = mcpResp.Error.Message
+				} else if mcpResp.Result.IsError {
+					for _, content := range mcpResp.Result.Content {
+						if content.Type == "text" {


probably don't need to check this since we only support text.

Yuan325 · 2026-04-09T22:02:27Z

tests/tool.go

+				if tc.wantBody == "" {
+					return
+				}


for mcp's cases, we might not want to skip these? seems like these are the ones that have content.IsError = true and might have a content.Text value? if needed we can add more field to the test cases struct such as wantContentErr string and set those as the string value.

Yuan325 · 2026-04-09T22:14:50Z

tests/option.go

 	supportArrayParam        bool
 	supportClientAuth        bool
 	supportSelect1Auth       bool
+	IsMCP                    bool


Suggested change

IsMCP bool

isMCP bool

shouldn't need to be exported. User should always set it with the function.

Yuan325 · 2026-04-09T22:30:24Z

tests/tool.go

+				wantStatus := tc.wantStatusCode
+				// MCP might return 200 OK for some error cases that REST returns 401
+				if wantStatus == http.StatusUnauthorized && mcpStatusCode == http.StatusOK {
+					wantStatus = http.StatusOK
+				}
+				if mcpStatusCode != wantStatus {
+					t.Errorf("StatusCode mismatch: got %d, want %d", mcpStatusCode, wantStatus)
+				}


Seems like the mcp status is always StatusOK. Lets just check if its statusOK. If there are test cases thats not statusOK, we can add a tc.wantStatusCodeMCP.

Suggested change

wantStatus := tc.wantStatusCode

// MCP might return 200 OK for some error cases that REST returns 401

if wantStatus == http.StatusUnauthorized && mcpStatusCode == http.StatusOK {

wantStatus = http.StatusOK

}

if mcpStatusCode != wantStatus {

t.Errorf("StatusCode mismatch: got %d, want %d", mcpStatusCode, wantStatus)

}

if mcpStatusCode != http.StatusOK {

t.Error("expected status ok")

}

Yuan325 · 2026-04-09T22:38:52Z

tests/tool.go

+				gotObj := getMCPResultText(t, mcpResp)
+				gotBytes, _ := json.Marshal(gotObj)
+				gotStr := string(gotBytes)
+
+				if strings.HasPrefix(strings.TrimSpace(tc.wantBody), "[") || strings.HasPrefix(strings.TrimSpace(tc.wantBody), "{") {
+					// It looks like JSON, let's do JSON comparison
+					var gotJSON, wantJSON any
+					_ = json.Unmarshal([]byte(gotStr), &gotJSON)
+					_ = json.Unmarshal([]byte(tc.wantBody), &wantJSON)

-			if got != tc.wantBody {
-				t.Fatalf("unexpected value: got %q, want %q", got, tc.wantBody)
+					if diff := cmp.Diff(wantJSON, gotJSON); diff != "" {
+						t.Fatalf("unexpected JSON value mismatch (-want +got):\n%s\nRaw got: %s\nRaw want: %s", diff, gotStr, tc.wantBody)
+					}
+				} else {
+					// Plain string, use strings.Contains as suggested by user
+					if !strings.Contains(gotStr, tc.wantBody) {
+						t.Fatalf(`expected %q to contain %q`, gotStr, tc.wantBody)
+					}
+				}


This comparison should be the same as the api endpoint? since they compare direct got != tc.wantBody, we should be able to do the same here too? rather than converting it to type any.

Yuan325 · 2026-04-09T22:39:01Z

tests/tool.go

-			if !ok {
-				t.Fatalf("unable to find result in response body")
-			}
+				// Extract error text if any


For the checks under here, we can check the Content.Text together regardless if it's "IsError".

E.g.

// first parse the content.Text to string // next check if isError is correct isError := tc.wantContentErr != "" if isError != mcpResp.Result.IsError { // throw t.Fatalf here } // check the content.Text string. if isError { // check content.Text with tc.wantContentErr } else { // check content.Text with tc.wantBody }

Yuan325 · 2026-04-09T23:11:07Z

tests/tool.go

-			if resp.StatusCode != tc.wantStatusCode {
-				t.Errorf("StatusCode mismatch: got %d, want %d. Response body: %s", resp.StatusCode, tc.wantStatusCode, string(respBody))
-			}
+			if configs.IsMCP {


did a quick draft --
we'll need to add wantContentErr string to the test case struct.

if configs.IsMCP { // Invoke the tool via MCP protocol mcpStatusCode, mcpResp, err := InvokeMCPTool(t, tc.toolName, tc.args, tc.requestHeader) if err != nil { t.Fatalf("native error executing %s: %s", tc.toolName, err) } if mcpStatusCode != http.StatusOK { t.Fatalf("expected status ok") } if tc.wantContentErr != "" { AssertMCPError(t, mcpResp, tc.wantContentErr) return } if mcpResp.Result.IsError { t.Fatalf("%s returned error result: %v", tc.toolName, mcpResp.Result) } gotObj := getMCPResultText(t, mcpResp) gotBytes, err := json.Marshal(gotObj) if err != nil { t.Fatalf("error marshaling result object") } if string(gotBytes) != tc.wantBody { var gotJSON, wantJSON any errGot := json.Unmarshal(gotBytes, &gotJSON) errWant := json.Unmarshal([]byte(tc.wantBody), &wantJSON) if errGot == nil && errWant == nil { if diff := cmp.Diff(wantJSON, gotJSON); diff != "" { t.Fatalf("unexpected JSON value mismatch (-want +got):\n%s\nRaw got: %s\nRaw want: %s", diff, got, tc.wantBody) } } else { t.Fatalf("unexpected value: got %q, want %q", got, tc.wantBody) } } } else {

dishaprakash changed the base branch from main to anubhav-feat-native-mcp-alloydb April 1, 2026 16:59

gemini-code-assist bot reviewed Apr 1, 2026

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dishaprakash force-pushed the mcp-cloud-sql-mysql-tests branch from db1827c to 7c651a9 Compare April 1, 2026 17:00

anubhav756 force-pushed the anubhav-feat-native-mcp-alloydb branch from 69bb59b to d81edf8 Compare April 1, 2026 17:03

dishaprakash changed the title ~~Mcp cloud sql mysql tests~~ test(source/cloud-sql-mysql): create MCP integration tests Apr 1, 2026

dishaprakash force-pushed the mcp-cloud-sql-mysql-tests branch from 94d7fce to e3fa5a6 Compare April 1, 2026 21:32

anubhav756 force-pushed the anubhav-feat-native-mcp-alloydb branch from d81edf8 to 4c21e3f Compare April 2, 2026 10:00

dishaprakash force-pushed the mcp-cloud-sql-mysql-tests branch from 0019b41 to 0a48e1c Compare April 2, 2026 12:38

anubhav756 force-pushed the anubhav-feat-native-mcp-alloydb branch 11 times, most recently from 16be479 to f643196 Compare April 4, 2026 13:13

dishaprakash force-pushed the mcp-cloud-sql-mysql-tests branch from 082b05d to 225d74f Compare April 6, 2026 09:38

anubhav756 force-pushed the anubhav-feat-native-mcp-alloydb branch from f643196 to 2e6e044 Compare April 7, 2026 07:25

dishaprakash marked this pull request as ready for review April 7, 2026 07:31

dishaprakash requested review from a team as code owners April 7, 2026 07:31

blunderbuss-gcf bot assigned Yuan325 Apr 7, 2026

anubhav756 force-pushed the anubhav-feat-native-mcp-alloydb branch from 2e6e044 to 5a9f6bd Compare April 7, 2026 07:32

dishaprakash force-pushed the mcp-cloud-sql-mysql-tests branch from e698ea1 to 072f36b Compare April 7, 2026 08:11

anubhav756 force-pushed the anubhav-feat-native-mcp-alloydb branch from 5a9f6bd to d2bdddd Compare April 7, 2026 08:17

Base automatically changed from anubhav-feat-native-mcp-alloydb to main April 7, 2026 08:42

dishaprakash and others added 24 commits April 9, 2026 22:15

add json aware comparision

9b3d686

fix tetss

6b9eae5

fix

d0a64e2

changes

4327892

fix

c261115

tests fix

8621690

fix tests

0b0fa11

fix tests

4fd8144

fix cockroachdb

b9d1a30

fix tests

4929422

fix tests

8950c2f

fix tests

d4ab394

code comments

8588d48

apply rules

cbbc657

simplify options

77c4689

fix imports

9ece0fd

Update option.go

7d807c6

update repo name

27f66d5

review changes

2f530c1

fix tests

ce49676

linter

c9108fc

update null for tests

53b15f1

linter fix

bc506e9

rebase to main and copy helper from alloydbpg pr

0910acf

dishaprakash force-pushed the mcp-cloud-sql-mysql-tests branch from 1aa40c7 to 0910acf Compare April 9, 2026 22:22

dishaprakash changed the base branch from anubhav-mcp-alloydbpg to main April 9, 2026 22:22

dishaprakash added the tests: run Label to trigger Github Action tests. label Apr 9, 2026

linter

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Yuan325 reviewed Apr 9, 2026

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test(source/cloud-sql-mysql): create MCP integration tests#2922

test(source/cloud-sql-mysql): create MCP integration tests#2922
dishaprakash wants to merge 31 commits intomainfrom
mcp-cloud-sql-mysql-tests

dishaprakash commented Apr 1, 2026 •

edited

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dishaprakash commented Apr 1, 2026 •

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