Add square-root exercise (#349)

config.json

@@ -664,6 +664,14 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 4
+      },
+      {
+        "slug": "square-root",
+        "name": "Square Root",
+        "uuid": "2fdce5b8-0cf3-4557-aca8-5f607887bef0",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 1
       }
     ]
   },

exercises/practice/square-root/.docs/instructions.md

@@ -0,0 +1,13 @@
+# Instructions
+
+Given a natural radicand, return its square root.
+
+Note that the term "radicand" refers to the number for which the root is to be determined.
+That is, it is the number under the root symbol.
+
+Check out the Wikipedia pages on [square root][square-root] and [methods of computing square roots][computing-square-roots].
+
+Recall also that natural numbers are positive real whole numbers (i.e. 1, 2, 3 and up).
+
+[square-root]: https://en.wikipedia.org/wiki/Square_root
+[computing-square-roots]: https://en.wikipedia.org/wiki/Methods_of_computing_square_roots

exercises/practice/square-root/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "erikschierboom"
+  ],
+  "files": {
+    "solution": [
+      "square-root.R"
+    ],
+    "test": [
+      "test_square-root.R"
+    ],
+    "example": [
+      ".meta/example.R"
+    ]
+  },
+  "blurb": "Given a natural radicand, return its square root.",
+  "source": "wolf99",
+  "source_url": "https://github.com/exercism/problem-specifications/pull/1582"
+}

exercises/practice/square-root/.meta/example.R

@@ -0,0 +1,12 @@
+square_root <- function(number) {
+  stopifnot(number > 0)
+
+  i <- 1
+  result <- 1
+  while (result <= number) {
+    i <- i + 1
+    result <- i^2
+  }
+
+  i - 1
+}

exercises/practice/square-root/.meta/tests.toml

@@ -0,0 +1,28 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[9b748478-7b0a-490c-b87a-609dacf631fd]
+description = "root of 1"
+
+[7d3aa9ba-9ac6-4e93-a18b-2e8b477139bb]
+description = "root of 4"
+
+[6624aabf-3659-4ae0-a1c8-25ae7f33c6ef]
+description = "root of 25"
+
+[93beac69-265e-4429-abb1-94506b431f81]
+description = "root of 81"
+
+[fbddfeda-8c4f-4bc4-87ca-6991af35360e]
+description = "root of 196"
+
+[c03d0532-8368-4734-a8e0-f96a9eb7fc1d]
+description = "root of 65025"

exercises/practice/square-root/square-root.R

@@ -0,0 +1,3 @@
+square_root <- function(number) {
+
+}

exercises/practice/square-root/test_square-root.R

@@ -0,0 +1,30 @@
+source("./square-root.R")
+library(testthat)
+
+test_that("Square root of 1 is 1", {
+  expect_equal(square_root(1), 1)
+})
+
+test_that("Square root of 4 is 2", {
+  expect_equal(square_root(4), 2)
+})
+
+test_that("Square root of 25 is 5", {
+  expect_equal(square_root(25), 5)
+})
+
+test_that("Square root of 81 is 9", {
+  expect_equal(square_root(81), 9)
+})
+
+test_that("Square root of 196 is 14", {
+  expect_equal(square_root(196), 14)
+})
+
+test_that("Square root of 65025 is 255", {
+  expect_equal(square_root(65025), 255)
+})
+
+test_that("Domain error for negative number", {
+  expect_error(square_root(-65536))
+})