roachtest: validate number of tables in database for fingerprinting

Continuing to get failures with missing tables in the backup fixtures,
this commit adds a stricter validation to our backup fixtures to ensure
that the number of tables are being fingerprinted. This should prevent
invalid fingerprints and fixtures from being created, which should
reduce our test failures on restore and isolate the failures to the real
culprit, the fixture tests.

Informs: #149671

Fixes: #149772, #149773, #149769

Release note: None

Author: kev-cao

pkg/cmd/roachtest/tests/backup_fixtures.go

@@ -49,6 +49,13 @@ import (
 // and rely on the managed identity to authenticate with Azure Blob Storage.
 const azureCredentialsFilePath = "/home/ubuntu/azure-credentials.yaml"
 
+// Maps a fixture database name to the expected number of tables in the
+// database, useful for verifying that the fingerprint of the fixture is as
+// expected.
+var expectedNumTables = map[string]int{
+	"tpcc": 9,
+}
+
 type BackupFixture interface {
 	Kind() string
 	// The database that is backed up.
@@ -468,6 +475,7 @@ func fingerprintDatabase(
 		t.L().Printf("no tables found in database %s", dbName)
 		return nil
 	}
+	require.Len(t, tables, expectedNumTables[dbName], "unexpected number of tables in database %s", dbName)
 	t.L().Printf("fingerprinting %d tables in database %s", len(tables), dbName)
 
 	fingerprints := make(map[string]string)
@@ -493,6 +501,10 @@ func fingerprintDatabase(
 		"fingerprinted %d tables in %s in %s",
 		len(tables), dbName, timeutil.Since(start),
 	)
+	require.Len(
+		t, fingerprints, expectedNumTables[dbName],
+		"unexpected number of fingerprints for database %s", dbName,
+	)
 	return fingerprints
 }
 
@@ -513,6 +525,7 @@ func getDatabaseTables(t test.Test, sql *sqlutils.SQLRunner, db string) []string
 		}
 		tables = append(tables, fmt.Sprintf(`%s.%s.%s`, db, schemaName, tableName))
 	}
+	require.NoError(t, rows.Err(), "error iterating over tables in database %s", db)
 	return tables
 }