# tests/testthat/test-utils.R

library(testthat)
library(Athlytics) # To make internal functions available if using devtools::load_all()
library(lubridate)

context("Utility Functions")

test_that("english_month_year correctly formats dates", {
  # Test with a single date
  single_date <- ymd("2023-01-15")
  expect_equal(english_month_year(single_date), "Jan 2023")

  # Test with multiple dates
  multiple_dates <- c(ymd("2023-03-10"), ymd("2024-11-05"))
  expect_equal(english_month_year(multiple_dates), c("Mar 2023", "Nov 2024"))

  # Test with dates spanning year-end
  year_end_dates <- c(ymd("2022-12-25"), ymd("2023-01-01"))
  expect_equal(english_month_year(year_end_dates), c("Dec 2022", "Jan 2023"))

  # Test with a leap year date
  leap_date <- ymd("2024-02-29")
  expect_equal(english_month_year(leap_date), "Feb 2024")
  
  # Test with an empty vector of dates (should return empty character vector)
  empty_dates <- ymd(character(0))
  expect_equal(english_month_year(empty_dates), character(0))
  
  # Test with NA date
  # expect_equal(english_month_year(ymd(NA)), NA_character_)
})

test_that("calculate_pace works correctly", {
  # Test standard pace calculation
  expect_equal(calculate_pace(3600, 10), 6)  # 1 hour for 10 km = 6 min/km
  expect_equal(calculate_pace(1800, 5), 6)   # 30 min for 5 km = 6 min/km
  
  # Test edge cases
  expect_equal(calculate_pace(0, 10), Inf)   # No time = infinite pace
  expect_equal(calculate_pace(3600, 0), Inf) # No distance = infinite pace
  
  # Test very fast pace
  expect_equal(calculate_pace(600, 3), 200/60)  # 10 min for 3 km
  
  # Test negative values
  expect_equal(calculate_pace(-100, 10), -10/60)
})