unit test calcx for #6

Former-commit-id: ce7b2b7
Former-commit-id: 42f5ce1

tests/testthat/test_calcx.R

@@ -0,0 +1,19 @@
+context("Calculating x position of correlation value")
+
+test_that("calcx return midpoint of width when correlation is 0", {
+  xpos <- calcx(0, width=200)
+  expect_equal(xpos, 100)
+})
+
+test_that("calcx without padding returns exactly devided values", {
+  expect_equal(calcx(-1, width=200, pad = 0), 0)
+  expect_equal(calcx(-0.5, width=200, pad = 0), 50)
+  expect_equal(calcx(0, width=200, pad = 0), 100)
+  expect_equal(calcx(0.5, width=200, pad = 0), 150)
+  expect_equal(calcx(1, width=200, pad = 0), 200)
+})
+
+test_that("calcx with padding avoids endpoints", {
+  expect_gt(calcx(-1), calcx(-1, pad = 0))
+  expect_lt(calcx(1), calcx(1, pad = 0))
+})