Expose REST API for delete an expense category, improve the error mes…

…sages and tests descriptions

server/src/main/java/io/myfinbox/account/application/CreateAccountService.java

@@ -23,7 +23,7 @@
 @RequiredArgsConstructor
 class CreateAccountService implements CreateAccountUseCase {
 
-    static final String ERROR_MESSAGE = "validation failed on create account request.";
+    static final String ERROR_MESSAGE = "Validation failed for the create account request.";
 
     private final CommandValidator validator = new CommandValidator();
     private final Accounts accounts;
@@ -36,7 +36,7 @@ public Either<Failure, Account> create(CreateAccountCommand cmd) {
         }
 
         if (accounts.existsByEmailAddress(new Account.EmailAddress(cmd.emailAddress()))) {
-            return Either.left(Failure.ofConflict("email address '%s' already exists.".formatted(cmd.emailAddress())));
+            return Either.left(Failure.ofConflict("Email address '%s' already exists.".formatted(cmd.emailAddress())));
         }
 
         var account = Account.builder()
@@ -66,7 +66,7 @@ private Validation<FieldViolation, String> validateFirstName(String firstName) {
 
             return Invalid(FieldViolation.builder()
                     .field(FIELD_FIRST_NAME)
-                    .message("first name length cannot be more than '%d'.".formatted(Account.MAX_LENGTH))
+                    .message("First name length cannot exceed '%d' characters.".formatted(Account.MAX_LENGTH))
                     .rejectedValue(firstName)
                     .build());
         }
@@ -79,7 +79,7 @@ private Validation<FieldViolation, String> validateLastName(String lastName) {
 
             return Invalid(FieldViolation.builder()
                     .field(FIELD_LAST_NAME)
-                    .message("last name length cannot be more than '%d'.".formatted(Account.MAX_LENGTH))
+                    .message("Last name length cannot exceed '%d' characters.".formatted(Account.MAX_LENGTH))
                     .rejectedValue(lastName)
                     .build());
         }
@@ -88,23 +88,23 @@ private Validation<FieldViolation, String> validateEmailAddress(String emailAddr
             if (StringUtils.isBlank(emailAddress)) {
                 return Invalid(FieldViolation.builder()
                         .field(FIELD_EMAIL_ADDRESS)
-                        .message("email address cannot be empty.")
+                        .message("Email address cannot be empty.")
                         .rejectedValue(emailAddress)
                         .build());
             }
 
             if (Account.MAX_LENGTH < emailAddress.length()) {
                 return Invalid(FieldViolation.builder()
                         .field(FIELD_EMAIL_ADDRESS)
-                        .message("email address length cannot be more than '%s'.".formatted(Account.MAX_LENGTH))
+                        .message("Email address length cannot exceed '%d' characters.".formatted(Account.MAX_LENGTH))
                         .rejectedValue(emailAddress)
                         .build());
             }
 
             if (!Pattern.compile(Account.patternRFC5322).matcher(emailAddress).matches()) {
                 return Invalid(FieldViolation.builder()
                         .field(FIELD_EMAIL_ADDRESS)
-                        .message("email address must follow RFC 5322 standard.")
+                        .message("Email address must follow RFC 5322 standard.")
                         .rejectedValue(emailAddress)
                         .build());
             }

server/src/main/java/io/myfinbox/expense/adapter/web/ExpenseCategoryController.java

@@ -12,8 +12,7 @@
 
 import static io.myfinbox.expense.application.CategoryService.CategoryCommand;
 import static org.springframework.http.MediaType.APPLICATION_JSON_VALUE;
-import static org.springframework.http.ResponseEntity.created;
-import static org.springframework.http.ResponseEntity.ok;
+import static org.springframework.http.ResponseEntity.*;
 import static org.springframework.web.servlet.support.ServletUriComponentsBuilder.fromCurrentRequest;
 
 @RestController
@@ -38,6 +37,12 @@ public ResponseEntity<?> update(@PathVariable UUID categoryId, @RequestBody Expe
                 .fold(apiFailureHandler::handle, category -> ok(toResource(category)));
     }
 
+    @DeleteMapping(path = "/{categoryId}", produces = APPLICATION_JSON_VALUE)
+    public ResponseEntity<?> delete(@PathVariable UUID categoryId) {
+        return categoryService.delete(categoryId)
+                .fold(apiFailureHandler::handle, ok -> noContent().build());
+    }
+
     private ExpenseCategoryResource toResource(Category category) {
         return new ExpenseCategoryResource()
                 .categoryId(category.getId().id())

server/src/main/java/io/myfinbox/expense/adapter/web/ExpenseCategoryControllerApi.java

@@ -22,7 +22,8 @@
 
 public interface ExpenseCategoryControllerApi {
 
-    @Operation(summary = "Add a new expense category in the MyFinBox", description = "Add a new expense category in the MyFinBox",
+    @Operation(summary = "Add a new expense category in the MyFinBox",
+            description = "Add a new expense category in the MyFinBox",
             security = {@SecurityRequirement(name = "openId")},
             tags = {TAG})
     @ApiResponses(value = {
@@ -40,7 +41,8 @@ public interface ExpenseCategoryControllerApi {
     })
     ResponseEntity<?> create(@RequestBody(description = "Expense Category Resource to be created", required = true) ExpenseCategoryResource resource);
 
-    @Operation(summary = "Update an expense category name in the MyFinBox", description = "Update an expense category name in the MyFinBox",
+    @Operation(summary = "Update an expense category name in the MyFinBox",
+            description = "Update an expense category name in the MyFinBox",
             security = {@SecurityRequirement(name = "openId")},
             tags = {TAG})
     @ApiResponses(value = {
@@ -59,4 +61,21 @@ public interface ExpenseCategoryControllerApi {
     })
     ResponseEntity<?> update(@Parameter(description = "CategoryId to be updated", required = true) UUID categoryId,
                              @RequestBody(description = "Expense Category Resource to be updated", required = true) ExpenseCategoryResource resource);
+
+    @Operation(summary = "Delete an expense category in the MyFinBox",
+            description = "Delete an expense category in the MyFinBox, if there are no expenses using the category",
+            security = {@SecurityRequirement(name = "openId")},
+            tags = {TAG})
+    @ApiResponses(value = {
+            @ApiResponse(responseCode = "204", description = "Successful Operation"),
+            @ApiResponse(responseCode = "400", description = "Malformed JSON or Type Mismatch Failure",
+                    content = @Content(mediaType = APPLICATION_JSON_VALUE, schema = @Schema(implementation = ApiErrorResponse.class))),
+            @ApiResponse(responseCode = "404", description = "Category not found",
+                    content = @Content(mediaType = APPLICATION_JSON_VALUE, schema = @Schema(implementation = ApiErrorResponse.class))),
+            @ApiResponse(responseCode = "409", description = "Category in-use",
+                    content = @Content(mediaType = APPLICATION_JSON_VALUE, schema = @Schema(implementation = ApiErrorResponse.class))),
+            @ApiResponse(responseCode = "500", description = "Internal Server Error",
+                    content = @Content(mediaType = APPLICATION_JSON_VALUE, schema = @Schema(implementation = ApiErrorResponse.class)))
+    })
+    ResponseEntity<?> delete(@Parameter(description = "CategoryId to be deleted", required = true) UUID categoryId);
 }

server/src/main/java/io/myfinbox/expense/application/CategoryService.java

@@ -38,6 +38,14 @@ public interface CategoryService {
      */
     Either<Failure, Category> update(UUID categoryId, CategoryCommand command);
 
+    /**
+     * Deletes a category based on the provided category ID.
+     *
+     * @param categoryId The ID of the category to delete.
+     * @return {@link Either} a {@link Failure} instance if the category deletion fails, or {@code null} if successful.
+     */
+    Either<Failure, Void> delete(UUID categoryId);
+
     record CategoryCommand(String name, UUID accountId) {
 
         public static final String FIELD_NAME = "name";

server/src/main/java/io/myfinbox/expense/application/CreateExpenseService.java

@@ -18,8 +18,8 @@
 @Transactional
 class CreateExpenseService implements CreateExpenseUseCase {
 
-    static final String VALIDATION_FAILURE_MESSAGE = "The validation for the create expense request has failed.";
-    static final String CATEGORY_NOT_FOUND_MESSAGE = "Category for the provided account was not found.";
+    static final String VALIDATION_FAILURE_MESSAGE = "Validation failed for the create expense request.";
+    static final String CATEGORY_NOT_FOUND_MESSAGE = "Category not found for the provided account.";
 
     private final ExpenseCommandValidator validator = new ExpenseCommandValidator();
 

server/src/main/java/io/myfinbox/expense/application/DefaultCategoryService.java

@@ -1,10 +1,7 @@
 package io.myfinbox.expense.application;
 
-import io.myfinbox.expense.domain.AccountIdentifier;
-import io.myfinbox.expense.domain.Categories;
-import io.myfinbox.expense.domain.Category;
+import io.myfinbox.expense.domain.*;
 import io.myfinbox.expense.domain.Category.CategoryIdentifier;
-import io.myfinbox.expense.domain.DefaultCategories;
 import io.myfinbox.shared.Failure;
 import io.myfinbox.shared.Failure.FieldViolation;
 import io.vavr.collection.Seq;
@@ -30,14 +27,16 @@
 @RequiredArgsConstructor
 class DefaultCategoryService implements CategoryService {
 
-    public static final String VALIDATION_CREATE_FAILURE_MESSAGE = "The validation for the create category expense request has failed.";
-    public static final String VALIDATION_UPDATE_FAILURE_MESSAGE = "The validation for the update category expense request has failed.";
-    public static final String CATEGORY_NAME_DUPLICATE_MESSAGE = "Category name already exists.";
-    public static final String CATEGORY_NOT_FOUND_MESSAGE = "Category not found.";
+    public static final String VALIDATION_CREATE_FAILURE_MESSAGE = "Validation failed for the create category expense request.";
+    public static final String VALIDATION_UPDATE_FAILURE_MESSAGE = "Validation failed for the update category expense request.";
+    public static final String CATEGORY_NAME_DUPLICATE_MESSAGE = "A category expense with the same name already exists.";
+    public static final String CATEGORY_NOT_FOUND_MESSAGE = "Category expense not found.";
+    public static final String CATEGORY_IN_USE_FAILURE_MESSAGE = "Category expense is currently in use.";
 
     private final CategoryCommandValidator validator = new CategoryCommandValidator();
 
     private final Categories categories;
+    private final Expenses expenses;
 
     @Override
     @Transactional
@@ -104,6 +103,27 @@ public Either<Failure, Category> update(UUID categoryId, CategoryCommand command
         return Either.right(category.get());
     }
 
+    @Override
+    @Transactional
+    public Either<Failure, Void> delete(UUID categoryId) {
+        if (isNull(categoryId)) {
+            return Either.left(Failure.ofNotFound(CATEGORY_NOT_FOUND_MESSAGE));
+        }
+
+        var category = categories.findById(new CategoryIdentifier(categoryId));
+        if (category.isEmpty()) {
+            return Either.left(Failure.ofNotFound(CATEGORY_NOT_FOUND_MESSAGE));
+        }
+
+        if (expenses.existsByCategory(category.get())) {
+            return Either.left(Failure.ofConflict(CATEGORY_IN_USE_FAILURE_MESSAGE));
+        }
+
+        categories.delete(category.get());
+
+        return Either.right(null);
+    }
+
     private static final class CategoryCommandValidator {
 
         Validation<Seq<FieldViolation>, CategoryCommand> validate(CategoryCommand command) {
@@ -127,7 +147,7 @@ private Validation<FieldViolation, String> validateName(String name) {
             if (!isBlank(name) && name.length() <= Category.NAME_MAX_LENGTH)
                 return Valid(name);
 
-            var message = format("Name length cannot be more than {0}.", Category.NAME_MAX_LENGTH);
+            var message = format("Name length cannot exceed {0} characters.", Category.NAME_MAX_LENGTH);
             if (isBlank(name))
                 message = "Name cannot be empty.";
 

server/src/main/java/io/myfinbox/expense/application/ExpenseCommandValidator.java

@@ -69,7 +69,7 @@ private Validation<FieldViolation, BigDecimal> validateAmount(BigDecimal amount)
             return Valid(amount);
         }
 
-        var message = "Amount must be positive value.";
+        var message = "Amount must be a positive value.";
         if (isNull(amount))
             message = "Amount cannot be null.";
 

server/src/main/java/io/myfinbox/expense/domain/Expenses.java

@@ -7,4 +7,7 @@
 
 @Repository
 public interface Expenses extends JpaRepository<Expense, ExpenseIdentifier> {
+
+    boolean existsByCategory(Category category);
+
 }

server/src/main/resources/db/migration/V4__expense_schema.sql

@@ -1,13 +1,13 @@
 CREATE TABLE IF NOT EXISTS expenses
 (
-    id                 UUID PRIMARY KEY DEFAULT gen_random_uuid(),
-    account_id         UUID     NOT NULL,
+    id                 UUID PRIMARY KEY        DEFAULT gen_random_uuid(),
+    account_id         UUID           NOT NULL,
     creation_timestamp TIMESTAMP      NOT NULL DEFAULT CURRENT_TIMESTAMP,
     payment_type       VARCHAR(20)    NOT NULL,
     amount             DECIMAL(19, 4) NOT NULL,
     currency           VARCHAR(3)     NOT NULL,
     expense_date       DATE           NOT NULL,
     description        TEXT,
-    category_id        UUID     NOT NULL,
+    category_id        UUID           NOT NULL,
     FOREIGN KEY (category_id) REFERENCES expensecategory (id)
 );

server/src/test/groovy/io/myfinbox/account/application/CreateAccountServiceSpec.groovy

@@ -14,8 +14,8 @@ import static org.apache.commons.lang3.RandomStringUtils.random
 @Tag("unit")
 class CreateAccountServiceSpec extends Specification {
 
-    static EMAIL_EMPTY_FIELD_ERROR = "email address cannot be empty."
-    static RFC_EMAIL_FIELD_ERROR = "email address must follow RFC 5322 standard."
+    static EMAIL_EMPTY_FIELD_ERROR = "Email address cannot be empty."
+    static RFC_EMAIL_FIELD_ERROR = "Email address must follow RFC 5322 standard."
 
     Accounts accounts
     CreateAccountService service
@@ -40,7 +40,7 @@ class CreateAccountServiceSpec extends Specification {
         assert either.getLeft() == Failure.ofValidation(CreateAccountService.ERROR_MESSAGE, [
                 Failure.FieldViolation.builder()
                         .field('firstName')
-                        .message("first name length cannot be more than '${Account.MAX_LENGTH}'.")
+                        .message("First name length cannot exceed '${Account.MAX_LENGTH}' characters.")
                         .rejectedValue(value)
                         .build()
         ])
@@ -61,7 +61,7 @@ class CreateAccountServiceSpec extends Specification {
         assert either.getLeft() == Failure.ofValidation(CreateAccountService.ERROR_MESSAGE, [
                 Failure.FieldViolation.builder()
                         .field('lastName')
-                        .message("last name length cannot be more than '${Account.MAX_LENGTH}'.")
+                        .message("Last name length cannot exceed '${Account.MAX_LENGTH}' characters.")
                         .rejectedValue(value)
                         .build()
         ])
@@ -106,7 +106,7 @@ class CreateAccountServiceSpec extends Specification {
         "a\"b(c)d,e:f;g<h>i[j\\k]l@example.com"      | RFC_EMAIL_FIELD_ERROR
         "this is\"not\\allowed@example.com"          | RFC_EMAIL_FIELD_ERROR
         "this\\ still\\\"not\\\\allowed@example.com" | RFC_EMAIL_FIELD_ERROR
-        "%s@gmail.com".formatted(randString(256))    | "email address length cannot be more than '${Account.MAX_LENGTH}'."
+        "%s@gmail.com".formatted(randString(256))    | "Email address length cannot exceed '${Account.MAX_LENGTH}' characters."
     }
 
     def "should create an account"() {

server/src/test/groovy/io/myfinbox/expense/DataSamples.groovy

@@ -19,7 +19,7 @@ class DataSamples {
     static accountId = "e2709aa2-7907-4f78-98b6-0f36a0c1b5ca"
     static categoryId = "3b257779-a5db-4e87-9365-72c6f8d4977d"
     static timestamp = "2024-03-23T10:00:04.224870Z"
-    static expenseDate = "2023-10-13"
+    static expenseDate = "2024-03-23"
     static amount = 10.0
     static currency = 'EUR'
 

server/src/test/groovy/io/myfinbox/expense/adapter/web/ExpenseCategoryControllerSpec.groovy

@@ -22,6 +22,7 @@ import spock.lang.Tag
 import static io.myfinbox.expense.DataSamples.newValidExpenseCategoryResource
 import static org.skyscreamer.jsonassert.JSONCompareMode.LENIENT
 import static org.springframework.boot.test.context.SpringBootTest.WebEnvironment.RANDOM_PORT
+import static org.springframework.http.HttpMethod.DELETE
 import static org.springframework.http.HttpMethod.PUT
 import static org.springframework.http.HttpStatus.*
 import static org.springframework.http.MediaType.APPLICATION_JSON
@@ -38,7 +39,7 @@ class ExpenseCategoryControllerSpec extends Specification {
     TestRestTemplate restTemplate
 
     def cleanup() {
-        JdbcTestUtils.deleteFromTables(jdbcTemplate, 'expensecategory')
+        JdbcTestUtils.deleteFromTables(jdbcTemplate, 'expenses', 'expensecategory')
     }
 
     def "Should create a new category expense"() {
@@ -101,6 +102,27 @@ class ExpenseCategoryControllerSpec extends Specification {
         JSONAssert.assertEquals(expectUpdateNotFoundFailure(), response.getBody(), LENIENT)
     }
 
+    @Sql('/expense/web/expensecategory-create.sql')
+    def "should delete an expense category"() {
+        when: 'expense category is deleted'
+        def response = deleteExpenseCategory()
+
+        then: 'response status is no content'
+        assert response.getStatusCode() == NO_CONTENT
+    }
+
+    @Sql(['/expense/web/expensecategory-create.sql', '/expense/web/expense-create.sql'])
+    def "Should fail delete when expense category is in use"() {
+        when: 'expense category fails to delete'
+        def response = deleteExpenseCategory()
+
+        then: 'response status is conflict'
+        assert response.getStatusCode() == CONFLICT
+
+        and: 'response body contains conflict failure response'
+        JSONAssert.assertEquals(expectDeleteConflictFailure(), response.getBody(), LENIENT)
+    }
+
     private postExpenseCategory(String request) {
         restTemplate.postForEntity('/expenses/category', entityRequest(request), String.class)
     }
@@ -114,6 +136,15 @@ class ExpenseCategoryControllerSpec extends Specification {
         )
     }
 
+    private deleteExpenseCategory() {
+        restTemplate.exchange(
+                "/expenses/category/${DataSamples.categoryId}",
+                DELETE,
+                entityRequest(null),
+                String.class
+        )
+    }
+
     def entityRequest(String req) {
         var headers = new HttpHeaders()
         headers.setContentType(APPLICATION_JSON)
@@ -142,7 +173,15 @@ class ExpenseCategoryControllerSpec extends Specification {
         JsonOutput.toJson([
                 status   : 404,
                 errorCode: 'NOT_FOUND',
-                message  : 'Category not found.'
+                message  : 'Category expense not found.'
+        ])
+    }
+
+    def expectDeleteConflictFailure() {
+        JsonOutput.toJson([
+                status   : 409,
+                errorCode: 'CONFLICT',
+                message  : 'Category expense is currently in use.'
         ])
     }
 }