[AFP-73] ✅ Add Manager model unit tests [@asegers]

backend/order-management/src/test/java/com/afp/ordermanagement/UNIT_TESTS/helper/ValidatableEntity.java

+package com.afp.ordermanagement.UNIT_TESTS.helper;
+
+import com.github.javafaker.Faker;
+//import com.sun.tools.javac.util.List;
+import org.junit.jupiter.api.Assertions;
+import static org.junit.jupiter.api.Assertions.*;
+
+
+import javax.validation.ConstraintViolation;
+import javax.validation.Validation;
+import javax.validation.Validator;
+import java.lang.reflect.ParameterizedType;
+import java.util.List;
+
+public abstract class ValidatableEntity<E> {
+    private final Class<E> childClass;
+
+    static private final Faker FAKER = new Faker();
+
+    @SuppressWarnings("unchecked")
+    public ValidatableEntity() {
+        this.childClass = (
+                (Class<E>) (
+                        (ParameterizedType) this.getClass()
+                        .getGenericSuperclass()
+                )
+                        .getActualTypeArguments()[0]
+        );
+    }
+
+    private static final Validator validator = Validation.buildDefaultValidatorFactory().getValidator();
+
+    // assertFieldValidation(String fieldName, Object input, boolean isValidInput)
+    public ConstraintViolation<E> createViolation(String fieldName, Object fieldValue) {
+        return validator
+                .validateValue(this.childClass, fieldName, fieldValue)
+                .stream()
+                .findAny()
+                .orElse(null);
+    }
+
+    // assertFieldValidation(String fieldName, Object input, boolean isValidInput)
+    public void assertFieldValidation(String fieldName, Object input, boolean expected) {
+        boolean isValid = validator.validateValue(this.childClass, fieldName, input).isEmpty();
+        String v = expected ? "valid" : "invalid";
+        String errMsg = String.format("Expected '%s' to be a %s value for field '%s'", input, v, fieldName);
+        if (isValid != expected) fail(errMsg);
+    }
+}

backend/order-management/src/test/java/com/afp/ordermanagement/UNIT_TESTS/model/ManagerTests.java

+package com.afp.ordermanagement.UNIT_TESTS.model;
+
+import com.afp.ordermanagement.UNIT_TESTS.helper.ValidatableEntity;
+import com.afp.ordermanagement.model.Manager;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class ManagerTests extends ValidatableEntity<Manager> {
+    @ParameterizedTest
+    @CsvSource(value = {"null:false", "\"\":false", "Jerry:true"}, delimiter = ':')
+    public void shouldValidateNameFields(String input, boolean expected) {
+        assertFieldValidation("firstName", input, expected);
+        assertFieldValidation("lastName", input, expected);
+    }
+
+    @ParameterizedTest
+    @CsvSource(value = {"null:false", "\"\":false", "poop:false", "jerry@hotmail.com:true"},  delimiter = ':')
+    public void shouldValidateEmailField(String input, boolean expected) {
+        assertFieldValidation("email", input, expected);
+
+    }
+
+    @ParameterizedTest
+    @CsvSource(value = {"null:false", "\"\":false"},  delimiter = ':')
+    public void shouldValidateGoogleIdField(String input, boolean expected) {
+        assertFieldValidation("googleId", input, expected);
+    }
+
+    @ParameterizedTest
+    @CsvSource(value = {"\"\",false", "https://picsum.photos/200,true", "htps: picsum.photos/200,false"})
+    public void shouldValidateImageUrl(String input, boolean expected) {
+        assertFieldValidation("imageUrl", input, expected);
+    }
+}