add Module.java class and ModuleTest.java

src/main/java/staffconnect/model/person/Module.java

@@ -0,0 +1,62 @@
+package staffconnect.model.person;
+
+import static java.util.Objects.requireNonNull;
+import static staffconnect.commons.util.AppUtil.checkArgument;
+
+/**
+ * Represents a Person's phone number in the staff book.
+ * Guarantees: immutable; is valid as declared in {@link #isValidModule(String)}
+ */
+public class Module {
+
+
+    public static final String MESSAGE_CONSTRAINTS =
+            "Module code should contain 2-4 capital letters followed by 4 digits long and at most 1 capitalised suffix";
+    public static final String VALIDATION_REGEX = "[A-Z]{2,5}\\d{4}[A-Z]{0,2}";
+
+    public final String value;
+
+    /**
+     * Constructs a {@code Module}.
+     *
+     * @param module A valid module code.
+     */
+    public Module(String module) {
+        requireNonNull(module);
+        checkArgument(isValidModule(module), MESSAGE_CONSTRAINTS);
+        value = module;
+    }
+
+    /**
+     * Returns true if a given string is a valid module code.
+     */
+    public static boolean isValidModule(String test) {
+        return test.matches(VALIDATION_REGEX);
+    }
+
+    @Override
+    public String toString() {
+        return value;
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (other == this) {
+            return true;
+        }
+
+        // instanceof handles nulls
+        if (!(other instanceof Module)) {
+            return false;
+        }
+
+        Module otherModule = (Module) other;
+        return value.equals(otherModule.value);
+    }
+
+    @Override
+    public int hashCode() {
+        return value.hashCode();
+    }
+
+}

src/test/java/staffconnect/model/person/ModuleTest.java

@@ -0,0 +1,66 @@
+package staffconnect.model.person;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static staffconnect.testutil.Assert.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class ModuleTest {
+
+    @Test
+    public void constructor_null_throwsNullPointerException() {
+        assertThrows(NullPointerException.class, () -> new Module(null));
+    }
+
+    @Test
+    public void constructor_invalidModule_throwsIllegalArgumentException() {
+        String invalidModule = "";
+        assertThrows(IllegalArgumentException.class, () -> new Module(invalidModule));
+    }
+
+    @Test
+    public void isValidModule() {
+        // null phone number
+        assertThrows(NullPointerException.class, () -> Module.isValidModule(null));
+
+        // invalid phone numbers
+        assertFalse(Module.isValidModule("")); // empty string
+        assertFalse(Module.isValidModule(" ")); // spaces only
+        assertFalse(Module.isValidModule("ABCD")); // letters only
+        assertFalse(Module.isValidModule("1234")); // numbers only
+        assertFalse(Module.isValidModule("2103T")); // missing prefix
+        assertFalse(Module.isValidModule("C2103T")); // only 1 prefix
+        assertFalse(Module.isValidModule("CS2103TTTT")); // too many suffix
+        assertFalse(Module.isValidModule("CSCSCS2103T")); // too many prefix
+        assertFalse(Module.isValidModule("CS210310101010T")); // too many numbers
+        assertFalse(Module.isValidModule("CS21T")); // too little numbers
+        assertFalse(Module.isValidModule("cs2103t")); // suffix not capitalised
+        assertFalse(Module.isValidModule("cs2103T")); // prefix not capitalised
+
+        // valid phone numbers
+        assertTrue(Module.isValidModule("CS2103")); // 2 prefix, 4 letters without 1 optional suffix
+        assertTrue(Module.isValidModule("CS2103T")); // 2 prefix, 4 letters with 1 optional suffix
+        assertTrue(Module.isValidModule("GEN2050")); // 3 prefix, 4 letters without  1 optional suffix
+        assertTrue(Module.isValidModule("GEN2050Y")); // 3 prefix, 4 letters with  1 optional suffix
+        assertTrue(Module.isValidModule("GESS1035")); // 4 prefix, 4 letters without 1 optional suffix
+        assertTrue(Module.isValidModule("GESS1035X")); // 4 prefix, 4 letters with  1 optional suffix
+    }
+
+    @Test
+    public void equals() {
+        Module module = new Module("CS2103");
+
+        // same values -> returns true
+        assertTrue(module.equals(new Module("CS2103")));
+
+        // same object -> returns true
+        assertTrue(module.equals(module));
+
+        // null -> returns false
+        assertFalse(module.equals(null));
+
+        // different values -> returns false
+        assertFalse(module.equals(new Module("MS2345")));
+    }
+}