Factor test tools between store and fragment

Those need the driver to deal with the fact that the store is stateful. Those
tests can't be moved to the test suite because they use private functions.

libraries/persistent_store/src/test.rs

@@ -0,0 +1,84 @@
+// Copyright 2021 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use crate::{BufferOptions, BufferStorage, Store, StoreDriverOff};
+
+#[derive(Clone)]
+pub struct Config {
+    word_size: usize,
+    page_size: usize,
+    num_pages: usize,
+    max_word_writes: usize,
+    max_page_erases: usize,
+}
+
+impl Config {
+    pub fn new_driver(&self) -> StoreDriverOff {
+        let options = BufferOptions {
+            word_size: self.word_size,
+            page_size: self.page_size,
+            max_word_writes: self.max_word_writes,
+            max_page_erases: self.max_page_erases,
+            strict_mode: true,
+        };
+        StoreDriverOff::new(options, self.num_pages)
+    }
+
+    pub fn new_store(&self) -> Store<BufferStorage> {
+        self.new_driver().power_on().unwrap().extract_store()
+    }
+}
+
+pub const MINIMAL: Config = Config {
+    word_size: 4,
+    page_size: 64,
+    num_pages: 5,
+    max_word_writes: 2,
+    max_page_erases: 9,
+};
+
+const NORDIC: Config = Config {
+    word_size: 4,
+    page_size: 0x1000,
+    num_pages: 20,
+    max_word_writes: 2,
+    max_page_erases: 10000,
+};
+
+const TITAN: Config = Config {
+    word_size: 4,
+    page_size: 0x800,
+    num_pages: 10,
+    max_word_writes: 2,
+    max_page_erases: 10000,
+};
+
+#[test]
+fn nordic_capacity() {
+    let driver = NORDIC.new_driver().power_on().unwrap();
+    assert_eq!(driver.model().capacity().total, 19123);
+}
+
+#[test]
+fn titan_capacity() {
+    let driver = TITAN.new_driver().power_on().unwrap();
+    assert_eq!(driver.model().capacity().total, 4315);
+}
+
+#[test]
+fn minimal_virt_page_size() {
+    // Make sure a virtual page has 14 words. We use this property in the other tests below to
+    // know whether entries are spanning, starting, and ending pages.
+    assert_eq!(MINIMAL.new_driver().model().format().virt_page_size(), 14);
+}