diff --git a/tests/testthat.R b/tests/testthat.R
new file mode 100644
index 0000000..b9a92ec
--- /dev/null
+++ b/tests/testthat.R
@@ -0,0 +1,4 @@
+library(testthat)
+library(slopes)
+
+test_check("slopes")
diff --git a/tests/testthat/test-slopes.R b/tests/testthat/test-slopes.R
new file mode 100644
index 0000000..3833ba4
--- /dev/null
+++ b/tests/testthat/test-slopes.R
@@ -0,0 +1,6 @@
+test_that("slope_* functions work", {
+  x = c(0, 2, 3, 4, 5, 9)
+  e = c(1, 2, 2, 4, 3, 1) / 10
+  expect_equal(slope_vector(x, e), c(0.05, 0, 0.2, -0.1, -0.05))
+  # expect_equal(slope_distance(x, e), c(0.05, 0, 0.2, -0.1, -0.05))
+})