Join tests

Author: lpil

src/gleam/string.gleam

@@ -435,19 +435,19 @@ fn repeat_loop(string: String, times: Int, acc: String) -> String {
 pub fn join(strings: List(String), with separator: String) -> String {
   case strings {
     [] -> ""
-    [first, ..rest] -> do_join(rest, separator, first)
+    [first, ..rest] -> join_loop(rest, separator, first)
   }
 }
 
-fn do_join(
+fn join_loop(
   strings: List(String),
   separator: String,
   accumulator: String,
 ) -> String {
   case strings {
     [] -> accumulator
     [string, ..strings] ->
-      do_join(strings, separator, accumulator <> separator <> string)
+      join_loop(strings, separator, accumulator <> separator <> string)
   }
 }
 

test/gleam/string_test.gleam

@@ -161,7 +161,27 @@ pub fn repeat_test() {
   |> should.equal("")
 }
 
-pub fn join_test() {
+pub fn join_0_test() {
+  []
+  |> string.join(with: ", ")
+  |> should.equal("")
+
+  []
+  |> string.join(with: "-")
+  |> should.equal("")
+}
+
+pub fn join_1_test() {
+  ["Hello"]
+  |> string.join(with: ", ")
+  |> should.equal("Hello")
+
+  ["Hello"]
+  |> string.join(with: "-")
+  |> should.equal("Hello")
+}
+
+pub fn join_2_test() {
   ["Hello", "world!"]
   |> string.join(with: ", ")
   |> should.equal("Hello, world!")
@@ -171,6 +191,16 @@ pub fn join_test() {
   |> should.equal("Hello-world!")
 }
 
+pub fn join_3_test() {
+  ["Hello", "there", "world!"]
+  |> string.join(with: ", ")
+  |> should.equal("Hello, there, world!")
+
+  ["Hello", "there", "world!"]
+  |> string.join(with: "-")
+  |> should.equal("Hello-there-world!")
+}
+
 pub fn trim_test() {
   "  hats  \n"
   |> string.trim