library(markovchain)

context("Checking that ExpectedTime function works as expected; it depends on ctmcd")
# Example from the book Markovchains, J. R. Norris, Cambridge University Press
states <- c("a","b","c","d")
byRow <- TRUE
gen <- matrix(data = c(-1, 1/2, 1/2, 0, 1/4, -1/2, 0, 1/4, 1/6, 0, -1/3, 1/6, 0, 0, 0, 0),
                  nrow = 4,byrow = byRow, dimnames = list(states,states))
ctmc <- new("ctmc",states = states, byrow = byRow, generator = gen, name = "testctmc")

test_that("Check Expected hitting time from one state to another",{
  # Skip the test if the ctmcd package is not available
  if (!requireNamespace("ctmcd", quietly = TRUE)) {
    skip("The ctmcd package is not available")
  }
  
  expect_equal(ExpectedTime(ctmc,1,4),7)
  expect_equal(ExpectedTime(ctmc,2,4),5.5)
})




context("Checking that probabilityatT function works as expected")
# TESTS for probabilityatT function
# Example taken from the book INTRODUCTION TO STOCHASTIC PROCESSES WITH R, ROBERT P. DOBROW, Wiley



states <- c("a","b","c","d","e")


# taken exactly from book
ansMatrix <- matrix(data = c(0.610, 0.290, 0.081, 0.016, 0.003,
                              0.232, 0.443, 0.238, 0.071, 0.017,
                              0.052, 0.190, 0.435, 0.238, 0.085,
                              0.008, 0.045, 0.191, 0.446, 0.310,
                              0.001, 0.008, 0.054, 0.248, 0.688),nrow = 5,byrow = T,dimnames = list(states,states))

byRow <- TRUE
gen <- matrix(c(-1/4,1/4,0,0,0,1/5,-9/20,1/4,0,0,0,1/5,-9/20,1/4,0,0,0,1/5,-9/20,1/4,0,0,0,1/5,-1/5),
              nrow=5,byrow=byRow, dimnames = list(states,states))

ctmc <- new("ctmc",states = states, byrow = byRow, generator = gen, name = "testctmc")

test_that("Check probabilityatT using a ctmc object:",{
  if (!requireNamespace("ctmcd", quietly = TRUE)) {
    skip("The ctmcd package is not available")
  }
  expect_equal(round(probabilityatT(ctmc,2.5),3),ansMatrix)
})


### Adds tests for impreciseprobabilityatT function
context("Checking that impreciseprobabilityatT function works as expected:")
states <- c("n","y")
Q <- matrix(c(-1,1,1,-1),nrow = 2,byrow = T,dimnames = list(states,states))
range <- matrix(c(1/52,3/52,1/2,2),nrow = 2,byrow = 2)
name <- "testictmc"
ictmc <- new("ictmc",states = states,Q = Q,range = range,name = name)


test_that("Check impreciseProbabilityatT function using an ictmc object:",{
  if (!requireNamespace("ctmcd", quietly = TRUE)) {
    skip("The ctmcd package is not available")
  }
  expect_equal(round(impreciseProbabilityatT(ictmc,2,0,1,error = 10^-3),4),c(0.0083,0.1410))
})


### Adds tests for freq2Generator function

sample <- matrix(c(150,2,1,1,1,200,2,1,2,1,175,1,1,1,1,150),nrow = 4,byrow = TRUE)
sample_rel = rbind((sample/rowSums(sample))[1:dim(sample)[1]-1,],c(rep(0,dim(sample)[1]-1),1)) 

answer <- matrix(c(
  -0.024,  0.015,  0.009,    0,
  0.007, -0.018,  0.012,    0,
  0.013 , 0.007, -0.021,    0,
  0.000,  0.000,  0.000,    0
),nrow = 4,byrow = TRUE)

test_that("Check if ",{
  if (!requireNamespace("ctmcd", quietly = TRUE)) {
    skip("The ctmcd package is not available")
  }
  expect_equal(round(freq2Generator(sample_rel,1),3),answer)
})

### tests for is.CTMCirreducible fcuntion

energyStates <- c("sigma", "sigma_star")
byRow <- TRUE
gen <- matrix(data = c(-3, 3,
                       1, -1), nrow = 2,
              byrow = byRow, dimnames = list(energyStates, energyStates))
molecularCTMC <- new("ctmc", states = energyStates, 
                     byrow = byRow, generator = gen, 
                     name = "Molecular Transition Model")

test_that("is.CTMCirreducible works", {
  if (!requireNamespace("ctmcd", quietly = TRUE)) {
    skip("The ctmcd package is not available")
  }
  expect_equal(is.CTMCirreducible(molecularCTMC),TRUE)
})


### tests for is.TimeReversible function

energyStates <- c("sigma", "sigma_star")
byRow <- TRUE
gen <- matrix(data = c(-3, 3,
                       1, -1), nrow = 2,
              byrow = byRow, dimnames = list(energyStates, energyStates))
molecularCTMC <- new("ctmc", states = energyStates, 
                     byrow = byRow, generator = gen, 
                     name = "Molecular Transition Model")

test_that("is.TimeReversible works", {
  if (!requireNamespace("ctmcd", quietly = TRUE)) {
    skip("The ctmcd package is not available")
  }
  expect_equal(is.TimeReversible(molecularCTMC),TRUE)
})