unit test/ci: report when unit test is using either TestServer/TestCluster API

[srosenberg]

To enable better tracking of flaky tests which rely on TestServer/TestCluster API [1], we'd like to surface a new parameter in GH issues. E.g., [2] is a unit test which failed during the nightly stress run; this test happens to use TestCluster API. See [3] for private slack discussion.

[1] https://cockroachlabs.atlassian.net/wiki/spaces/CRDB/pages/3155427384/TestServer+and+TestCluster
[2] #110187
[3] https://cockroachlabs.slack.com/archives/C023S0V4YEB/p1695754554482619

Jira issue: CRDB-31874

[blathers-crl]

cc @cockroachdb/test-eng

[srosenberg]

I've made a quick & dirty patch to extract the info. using call stack frames. The diff is below. I am also attaching the resulting tests, which use TestServer/TestCluster, at this time, on master.

diff --git a/pkg/server/testserver.go b/pkg/server/testserver.go
index f5554d65b0c..97097591cc3 100644
--- a/pkg/server/testserver.go
+++ b/pkg/server/testserver.go
@@ -19,6 +19,7 @@ import (
        "net/http"
        "os"
        "path/filepath"
+       "runtime"
        "strconv"
        "strings"
        "time"
@@ -63,6 +64,7 @@ import (
        "github.com/cockroachdb/cockroach/pkg/upgrade/upgradebase"
        "github.com/cockroachdb/cockroach/pkg/util"
        "github.com/cockroachdb/cockroach/pkg/util/admission"
+       "github.com/cockroachdb/cockroach/pkg/util/allstacks"
        "github.com/cockroachdb/cockroach/pkg/util/hlc"
        "github.com/cockroachdb/cockroach/pkg/util/log"
        "github.com/cockroachdb/cockroach/pkg/util/metric"
@@ -2311,6 +2313,64 @@ func (testServerFactoryImpl) PrepareRangeTestServer(srv interface{}) error {
        return nil
 }

+// getTestName returns the calling test function name, returning an empty string
+// if not found. The number of calls up the call stack is limited.
+func getTestName() string {
+       pcs := make([]uintptr, 20)
+       n := runtime.Callers(2, pcs)
+       frames := runtime.CallersFrames(pcs[:n])
+       match := func(s string) bool {
+               return strings.Contains(s, ".Test") || strings.Contains(s, ".Benchmark") ||
+                       strings.Contains(s, ".Example")
+       }
+
+       for {
+               frame, more := frames.Next()
+               fxn := frame.Function
+               if match(fxn) {
+                       return fxn
+               }
+               if !more {
+                       break
+               }
+       }
+       // No luck, the test must be on a different stack; e.g., datadriven tests use a goroutine for each subtest.
+       // Let's grab all the stacks and match anything that looks like a test function other than TestMain.
+       buf := allstacks.Get()
+       for _, g := range strings.Split(string(buf), "\n\n") {
+               sl := strings.SplitN(g, "\n", 2)
+               if len(sl) != 2 {
+                       continue
+               }
+               stack := strings.TrimSpace(sl[1])
+               // N.B. skip stack if it contains TestMain, as that's the entry point for the test binary.
+               if !strings.Contains(stack, ".TestMain(") && match(stack) {
+                       lines := strings.Split(stack, "\n")
+                       for _, line := range lines {
+                               if match(line) {
+                                       i := strings.Index(line, ".Test")
+                                       if i == -1 {
+                                               i = strings.Index(line, ".Benchmark")
+                                       }
+                                       if i == -1 {
+                                               i = strings.Index(line, ".Example")
+                                       }
+                                       if i != -1 {
+                                               line = line[i+1:]
+                                               i = strings.Index(line, "(")
+                                               if i != -1 {
+                                                       line = line[:i]
+
+                                                       return line
+                                               }
+                                       }
+                               }
+                       }
+               }
+       }
+       return ""
+}
+
 // New is part of TestServerFactory interface.
 func (testServerFactoryImpl) New(params base.TestServerArgs) (interface{}, error) {
        if params.Knobs.JobsTestingKnobs != nil {
@@ -2320,6 +2380,9 @@ func (testServerFactoryImpl) New(params base.TestServerArgs) (interface{}, error
                        }
                }
        }
+       // determine the top-level test function name
+       testName := getTestName()
+       fmt.Println("TestServerFactoryImpl::New", testName)

        cfg := makeTestConfigFromParams(params)
        ts := &testServer{Cfg: &cfg, params: params}

[srosenberg]

tests_using_TestServer.log