Add unit test suite for all game modules

[yashamin11]

Summary

Adds test_melonland.py — a full unit test suite covering every module in the project. Pygame is mocked via unittest.mock so tests run headlessly with no display or asset files required.

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Test Cases

TestGlobalSettings — verifies the central config values

Test	What it checks
test_title	Game title is "MelonLand"
test_number_of_levels	There are exactly 5 levels
test_grid_factors	xFactor and yFactor are both 80
test_grid_dimensions	Grid is 10×10
test_screen_width	screenWidth = (cols+1) × xFactor = 880
test_screen_height	screenHeight = (rows+2) × yFactor = 960
test_fixed_obstacle_score	fobsScore = 5
test_moving_obstacle_score	mobsScore = 10
test_completion_bonus	completeScore = 25
test_time_penalty	timePenalty = 2
test_dying_penalty	dyingPenalty = 50
test_color_black/white/green/red	All colour tuples are correct RGB values
test_*_image_path	Asset paths contain the expected filename
test_start/end_screen_messages	UI strings contain the right keywords

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TestPlayer — verifies movement, scoring, and collision logic

Test	What it checks
test_initial_score_is_zero	Player starts with score 0
test_initial_not_invincible	isInvincible defaults to False
test_initial_grid_coords_zero	gridX and gridY start at 0
test_player_number_stored	Player stores its number (1 or 2)
test_velocity_equals_grid_factor	xVel/yVel match xFactor/yFactor
test_move_up_decrements_y	Moving up subtracts yVel from y
test_move_down_increments_y	Moving down adds yVel to y
test_move_left_decrements_x	Moving left subtracts xVel from x
test_move_right_increments_x	Moving right adds xVel to x
test_move_up_updates_gridY	gridY tracks position correctly after moving up
test_move_down_updates_gridY	gridY tracks position correctly after moving down
test_left_right_do_not_change_gridY	Horizontal moves don't affect gridY
test_p1_up_step1_earns_fobs_score	Player 1 moving into an odd row earns +5
test_p1_up_step2_earns_mobs_score	Player 1 moving into an even row earns +10
test_p1_down_step1_loses_mobs_score	Player 1 moving backwards into odd row loses 10
test_p1_down_step2_loses_fobs_score	Player 1 moving backwards into even row loses 5
test_p2_down_step1_earns_fobs_score	Player 2 moving into an odd row earns +5
test_p2_down_step2_earns_mobs_score	Player 2 moving into an even row earns +10
test_p2_up_step1_loses_mobs_score	Player 2 moving backwards into odd row loses 10
test_p2_up_step2_loses_fobs_score	Player 2 moving backwards into even row loses 5
test_is_collided_full_overlap	Two completely overlapping objects collide
test_is_collided_partial_overlap_x	Objects overlapping by 1px on x-axis collide
test_no_collision_obstacle_right_of_player	Object fully to the right does not collide
test_no_collision_obstacle_left_of_player	Object fully to the left does not collide
test_no_collision_obstacle_below_player	Object fully below does not collide
test_no_collision_obstacle_above_player	Object fully above does not collide
test_touching_x_edge_is_collision	Objects sharing an edge (touching) count as a collision
test_touching_y_edge_is_collision	Same as above on the y-axis
test_invincible_player_never_collides	Invincible player is immune to all collisions
test_invincible_player_no_collision_even_when_overlapping	Invincibility holds even when completely inside an obstacle

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TestFixedObstacle — verifies void obstacle placement and size

Test	What it checks
test_position_at_origin	Obstacle at row=0, col=0 has x=0, y=0
test_position_scaled_by_factor	x = col × xFactor, y = row × yFactor
test_x_uses_col	x coordinate derived from col, not row
test_y_uses_row	y coordinate derived from row, not col
test_width_equals_x_factor	width fills exactly one grid cell
test_height_equals_y_factor	height fills exactly one grid cell
test_row_and_col_stored	row and col attributes saved correctly
test_color_is_black	Obstacle colour is (0, 0, 0)

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TestMovingObstacle — verifies knife movement and screen wrapping

Test	What it checks
test_initial_position_scaled	Position = col × xFactor, row × yFactor
test_width_and_height_equal_factor	Fills exactly one grid cell
test_row_col_direc_stored	row, col, direc attributes saved correctly
test_velocity_stored	obsVel attribute saved correctly
test_move_right_increments_x	direc=1 adds obsVel to x each step
test_move_left_decrements_x	direc=0 subtracts obsVel from x each step
test_move_does_not_change_y	Movement is horizontal only
test_move_accumulates_over_multiple_steps	5 steps of vel=3 moves x by 15 total
test_right_mover_wraps_when_past_right_edge	x > screenWidth resets to -xFactor
test_right_mover_no_wrap_exactly_at_boundary	x == screenWidth does not trigger wrap
test_left_mover_wraps_when_past_left_edge	x < -xFactor resets to screenWidth
test_left_mover_no_wrap_exactly_at_boundary	x == -xFactor does not trigger wrap
test_right_mover_ignores_left_exit	Right-moving knife ignores left-side overflow
test_left_mover_ignores_right_exit	Left-moving knife ignores right-side overflow

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TestLevel — verifies level setup and obstacle management

Test	What it checks
test_difficulty_equals_lvl_plus_one	diff = lvl + 1 for all 5 levels
test_initial_obstacle_lists_empty	No obstacles exist before createObstacles()
test_players_reference_stored	Level holds the same players list passed in
test_level_number_stored	lvl attribute saved correctly
test_obstacle_count_level_1	Level 1 creates 8 fixed + 10 moving obstacles
test_obstacle_count_level_2	Level 2 creates 12 fixed + 15 moving obstacles
test_obstacle_count_level_5	Level 5 creates 24 fixed + 30 moving obstacles
test_higher_level_has_more_obstacles	Level 3 has more obstacles than Level 1
test_obstacle_types_are_correct_classes	fixedObstacles contain FixedObstacle, movingObstacles contain MovingObstacle
test_fixed_obstacles_placed_on_even_rows	All fixed obstacles land on rows 2, 4, 6, 8
test_moving_obstacles_placed_on_odd_rows	All moving obstacles land on rows 1, 3, 5, 7, 9
test_moving_obstacles_velocity_equals_difficulty	Knife speed scales with level difficulty
test_create_obstacles_called_twice_doubles_count	createObstacles() appends, doesn't reset
test_destroy_after_create_empties_lists	destroyObstacles() clears both lists
test_destroy_on_empty_level_is_safe	Calling destroy with no obstacles doesn't crash
test_create_after_destroy_repopulates	Create → destroy → create gives correct counts again

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How to run

python3 -m pytest test_melonland.py -v
# or
python3 -m unittest test_melonland -v

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