Add information about writing tests

tutorials/ab3AddRemark.md

@@ -11,13 +11,18 @@ Let's walk you through the implementation of a new command — `remark`.
 This command allows users of the AddressBook application to add optional remarks to people in their address book and edit it if required. The command should have the following format:
 
 `remark INDEX r/REMARK`
-* `INDEX`: Refers to the position of the person in the currently displayed list on the GUI.
-* `REMARK`: Is the note you wish to attach to their entry.
+
+- `INDEX`: Refers to the position of the person in the currently displayed list on the GUI.
+- `REMARK`: Is the note you wish to attach to their entry.
 
 For example, `remark 2 r/Likes baseball` adds the remark “Likes baseball” to the person at position 2 in the currently displayed list.
 
 We’ll assume that you have already set up the development environment as outlined in the Developer’s Guide.
 
+<panel header="Writing tests">
+
+It’s crucial to ensure that our code behaves as expected. This is why we write tests at each step of the process. These tests not only verify that the new functionality works correctly but also help prevent future changes from inadvertently breaking the code. You will find the implementation details of these tests in panels like this one. For more information about JUnit, refer to [this](http://se-education.org/guides/tutorials/junit.html).
+</panel>
 
 ## Create a new `remark` command
 
@@ -52,6 +57,28 @@ public class RemarkCommand extends Command {
 
 Now that we have our `RemarkCommand` ready to be executed, we need to update `AddressBookParser#parseCommand()` to recognize the `remark` keyword. Add the new command to the `switch` block by creating a new `case` that returns a new instance of `RemarkCommand`.
 
+<panel header="Create `RemarkCommandTest`">
+
+- Since we created a new file RemarkCommand, we should also create a `RemarkCommandTest` file. JUnit tests are annotated with `@Test`. For now, we expect `execute` in `RemarkCommand` to fail. Thus, the test will reflect this expectation.
+
+- ```java
+    @Test
+    public void execute() {
+        assertCommandFailure(new RemarkCommand(), model, MESSAGE_NOT_IMPLEMENTED_YET);
+    }
+  ```
+
+- Don’t forget to include a test case in `AddressBookParserTest` to ensure that a `RemarkCommand` is created when the command is parsed successfully.
+
+- ```java
+    @Test
+    public void parseCommand_remark() throws Exception {
+        assertTrue(parser.parseCommand(RemarkCommand.COMMAND_WORD) instanceof RemarkCommand);
+    }
+  ```
+
+</panel>
+
 You can refer to the changes in this [diff](https://github.com/se-edu/addressbook-level3/commit/35eb7286f18a029d39cb7a29df8f172a001e4fd8#diff-399c284cb892c20b7c04a69116fcff6ccc0666c5230a1db8e4a9145def8fa4ee).
 
 ### Run the application
@@ -141,6 +168,53 @@ public class RemarkCommand extends Command {
 }
 ```
 
+<panel header="Update construction of `RemarkCommand` in `RemarkCommandTest`">
+
+- Since `RemarkCommand` now requires both an index and a remark for instantiation, the tests should be updated accordingly. Additionally, the execution of the command has been updated, so the tests should be adjusted to reflect these changes.
+- ```java
+    @Test
+    public void execute() {
+    final String remark = "Some remark";
+
+    assertCommandFailure(new RemarkCommand(INDEX_FIRST_PERSON, remark), model,
+        String.format(MESSAGE_ARGUMENTS, INDEX_FIRST_PERSON.getOneBased(), remark));
+    }
+  ```
+
+- Note: you can use `CommandTestUtil.java` to include constant test values for greater reusability.
+- ```java
+    public static final String VALID_REMARK_AMY = "Like skiing.";
+    public static final String VALID_REMARK_BOB = "Favourite pastime: Eating";
+  ```
+- Additionally, we can add tests for the `equals` method for various inputs, like objects of the different values or types.
+- ```java
+    @Test
+    public void equals() {
+        final RemarkCommand standardCommand = new RemarkCommand(INDEX_FIRST_PERSON, VALID_REMARK_AMY);
+
+        // same values -> returns true
+        RemarkCommand commandWithSameValues = new RemarkCommand(INDEX_FIRST_PERSON, VALID_REMARK_AMY);
+        assertTrue(standardCommand.equals(commandWithSameValues));
+
+        // same object -> returns true
+        assertTrue(standardCommand.equals(standardCommand));
+
+        // null -> returns false
+        assertFalse(standardCommand.equals(null));
+
+        // different types -> returns false
+        assertFalse(standardCommand.equals(new ClearCommand()));
+
+        // different index -> returns false
+        assertFalse(standardCommand.equals(new RemarkCommand(INDEX_SECOND_PERSON, VALID_REMARK_AMY)));
+
+        // different remark -> returns false
+        assertFalse(standardCommand.equals(new RemarkCommand(INDEX_FIRST_PERSON, VALID_REMARK_BOB)));
+    }
+  ```
+
+</panel>
+
 Your code should look something like [this](https://github.com/se-edu/addressbook-level3/commit/dc6d5139d08f6403da0ec624ea32bd79a2ae0cbf#diff-a8e35af8f9c251525063fae36c9852922a7e7195763018eacec60f3a4d87c594) after you are done.
 
 ### Parse user input
@@ -222,9 +296,41 @@ public RemarkCommand parse(String args) throws ParseException {
 <box type="info" seamless>
 
 Don’t forget to update `AddressBookParser` to use our new `RemarkCommandParser`!
-
 </box>
 
+<panel header="Adding `RemarkCommandParserTest`">
+
+`RemarkCommandParserTest` should also be included to ensure that `RemarkCommandParser` works as we expect. Write test cases that cover a wide range of user inputs, such as presence of index and fields.
+
+```java
+@Test
+public void parse_indexSpecified_success() {
+    // have remark
+    Index targetIndex = INDEX_FIRST_PERSON;
+    String userInput = targetIndex.getOneBased() + " " + PREFIX_REMARK + nonEmptyRemark;
+    RemarkCommand expectedCommand = new RemarkCommand(INDEX_FIRST_PERSON, nonEmptyRemark);
+    assertParseSuccess(parser, userInput, expectedCommand);
+
+    // no remark
+    userInput = targetIndex.getOneBased() + " " + PREFIX_REMARK;
+    expectedCommand = new RemarkCommand(INDEX_FIRST_PERSON, "");
+    assertParseSuccess(parser, userInput, expectedCommand);
+}
+
+@Test
+public void parse_missingCompulsoryField_failure() {
+    String expectedMessage = String.format(MESSAGE_INVALID_COMMAND_FORMAT, RemarkCommand.MESSAGE_USAGE);
+
+    // no parameters
+    assertParseFailure(parser, RemarkCommand.COMMAND_WORD, expectedMessage);
+
+    // no index
+    assertParseFailure(parser, RemarkCommand.COMMAND_WORD + " " + nonEmptyRemark, expectedMessage);
+}
+```
+
+</panel>
+
 If you are stuck, check out the sample
 [here](https://github.com/se-edu/addressbook-level3/commit/dc6d5139d08f6403da0ec624ea32bd79a2ae0cbf#diff-8bf239e8e9529369b577701303ddd96af93178b4ed6735f91c2d8488b20c6b4a).
 
@@ -256,14 +362,13 @@ Simply add the following to [`seedu.address.ui.PersonCard`](https://github.com/s
 private Label remark;
 ```
 
-
 `@FXML` is an annotation that marks a private or protected field and makes it accessible to FXML. It might sound like Greek to you right now, don’t worry — we will get back to it later.
 
 Then insert the following into [`main/resources/view/PersonListCard.fxml`](https://github.com/se-edu/addressbook-level3/commit/850b78879582f38accb05dd20c245963c65ea599#diff-d44c4f51c24f6253c277a2bb9bc440b8064d9c15ad7cb7ceda280bca032efce9).
 
 **`PersonListCard.fxml`:**
 
-``` xml
+```xml
 <Label fx:id="remark" styleClass="cell_small_label" text="\$remark" />
 ```
 
@@ -289,8 +394,19 @@ Use the `Find Usages` feature in IntelliJ IDEA on the `Person` class to find the
 
 </box>
 
-Refer to [this commit](https://github.com/se-edu/addressbook-level3/commit/ce998c37e65b92d35c91d28c7822cd139c2c0a5c) and check that you have got everything in order!
+<panel header= "Update default `Person` in tests">
 
+`PersonBuilder.java` is used to create a default `Person` object for testing purposes. Don’t forget to include a remark field in this default Person too!
+
+```java
+public Person build() {
+    return new Person(name, phone, email, address, remark, tags);
+}
+```
+
+</panel>
+
+Refer to [this commit](https://github.com/se-edu/addressbook-level3/commit/ce998c37e65b92d35c91d28c7822cd139c2c0a5c) and check that you have got everything in order!
 
 ## Updating Storage
 
@@ -304,6 +420,21 @@ You must delete AddressBook’s storage file located at `/data/addressbook.json`
 
 </box>
 
+<panel header="Update `Person` objects for testing">
+
+`TypicalPersons.java` is used to create various `Person` objects for testing. Add the remark field for these `Person` objects!
+
+```java
+public static final Person ALICE = new PersonBuilder()
+    .withName("Alice Pauline")
+    .withAddress("123, Jurong West Ave 6, #08-111").withEmail("[email protected]")
+    .withPhone("94351253")
+    .withPhone("94351253").withRemark("She likes aardvarks.")
+    .withTags("friends").build();
+```
+
+</panel>
+
 Check out [this commit](https://github.com/se-edu/addressbook-level3/commit/556cbd0e03ff224d7a68afba171ad2eb0ce56bbf)
 to see what the changes entail.