Avoid changing H2 DB files when running tests (#29472)

* Avoid updating tiny-db in ssh test

* Avoid updating sample-database during testing

* Fix write test

test/metabase/sample_data_test.clj

@@ -20,8 +20,11 @@
 
 ;; These tools are pretty sophisticated for the amount of tests we have!
 
-(defn- sample-database-db []
-  {:details (#'sample-data/try-to-extract-sample-database!)
+(defn- sample-database-db [read-write?]
+  ;; If `read-write?` is false, open the DB in read-only mode so we don't accidentally modify it during testing
+  {:details (cond-> (#'sample-data/try-to-extract-sample-database!)
+              (not read-write?)
+              (update :db #(str % ";ACCESS_MODE_DATA=r")))
    :engine  :h2
    :name    "Sample Database"})
 
@@ -29,7 +32,7 @@
   "Execute `body` with a temporary Sample Database DB bound to `db-binding`."
   {:style/indent 1}
   [[db-binding] & body]
-  `(mt/with-temp Database [db# (sample-database-db)]
+  `(mt/with-temp Database [db# (sample-database-db false)]
      (sync/sync-database! db#)
      (let [~db-binding db#]
        ~@body)))
@@ -47,7 +50,7 @@
 
 ;;; ----------------------------------------------------- Tests ------------------------------------------------------
 
-(def ^:private extracted-db-path-regex #"^file:.*plugins/sample-database.db;USER=GUEST;PASSWORD=guest$")
+(def ^:private extracted-db-path-regex #"^file:.*plugins/sample-database.db;USER=GUEST;PASSWORD=guest.*")
 
 (deftest extract-sample-database-test
   (testing "The Sample Database is copied out of the JAR into the plugins directory before the DB details are saved."
@@ -104,7 +107,8 @@
 
 (deftest write-rows-sample-database-test
   (testing "should be able to execute INSERT, UPDATE, and DELETE statements on the Sample Database"
-    (with-temp-sample-database-db [db]
+    (mt/with-temp Database [db (sample-database-db true)]
+      (sync/sync-database! db)
       (mt/with-db db
         (let [conn-spec (sql-jdbc.conn/db->pooled-connection-spec (mt/db))]
           (testing "update row"

test/metabase/util/ssh_test.clj

@@ -251,7 +251,8 @@
       (testing "ssh tunnel is reestablished if it becomes closed, so subsequent queries still succeed (H2 version)"
         (let [h2-port (tu/find-free-port)
               server  (init-h2-tcp-server h2-port)
-              uri     (format "tcp://localhost:%d/./test_resources/ssh/tiny-db;USER=GUEST;PASSWORD=guest" h2-port)
+              ; Use ACCESS_MODE_DATA=r to avoid updating the DB file
+              uri     (format "tcp://localhost:%d/./test_resources/ssh/tiny-db;USER=GUEST;PASSWORD=guest;ACCESS_MODE_DATA=r" h2-port)
               h2-db   {:port               h2-port
                        :host               "localhost"
                        :db                 uri