Convert bool string comparisons to strconv.ParseBool for REST parameters (#13650)

* Convert bool string comparisons to strconv.ParseBool for REST parameters

* Log failed bool conversions

* Rename errors, changed log levels

* drop strconv.ParseBool error handling

If the query string parameter is omitted, strconv.ParseBool returns an error for the empty strings, which spams the logs. Instead, just assume the default semantics of a `false` return value if an error occurs.

* allow randomized Client4 booleans

It's hard to test api4's handling of the various boolean input values
accepted. Extend Client4 with support for overriding how it builds those
strings, and pick a random value on test startup.

* gofmt -s

Co-authored-by: mattermod <mattermod@users.noreply.github.com>
Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>
Co-authored-by: Jesse Hallam <jesse.hallam@gmail.com>

api4/apitestlib.go

@@ -6,6 +6,7 @@ package api4
 import (
 	"fmt"
 	"io/ioutil"
+	"math/rand"
 	"net"
 	"net/http"
 	"os"
@@ -153,6 +154,16 @@ func setupTestHelper(dbStore store.Store, searchEngine *searchengine.Broker, ent
 	th.Client = th.CreateClient()
 	th.SystemAdminClient = th.CreateClient()
 
+	// Verify handling of the supported true/false values by randomizing on each run.
+	rand.Seed(time.Now().UTC().UnixNano())
+	trueValues := []string{"1", "t", "T", "TRUE", "true", "True"}
+	falseValues := []string{"0", "f", "F", "FALSE", "false", "False"}
+	trueString := trueValues[rand.Intn(len(trueValues))]
+	falseString := falseValues[rand.Intn(len(falseValues))]
+	mlog.Debug("Configured Client4 bool string values", mlog.String("true", trueString), mlog.String("false", falseString))
+	th.Client.SetBoolString(true, trueString)
+	th.Client.SetBoolString(false, falseString)
+
 	th.LocalClient = th.CreateLocalClient(*config.ServiceSettings.LocalModeSocketLocation)
 
 	if th.tempWorkspace == "" {