add tests for runtime decode errors

1 files changed, 72 insertions, 0 deletions

diff --git a/test/gleam_json_js_ffi_test.gleam b/test/gleam_json_js_ffi_test.gleam
new file mode 100644
index 0000000..74d1867
--- /dev/null
+++ b/test/gleam_json_js_ffi_test.gleam
@@ -0,0 +1,72 @@
+import gleeunit
+import gleam/json.{DecodeError, UnexpectedByte, UnexpectedEndOfInput}
+import gleeunit/should
+
+if javascript {
+  pub fn main() {
+    gleeunit.main()
+  }
+}
+
+type StandardError {
+  StandardError(message: String)
+}
+
+// === End of input tests === //
+pub fn chromium_end_of_input_test() {
+  "Unexpected end of JSON input"
+  |> StandardError
+  |> get_json_decode_error("")
+  |> should.equal(UnexpectedEndOfInput)
+}
+
+pub fn spidermonkey_end_of_input_test() {
+  "JSON.parse: unexpected end of data at line 1 column 1 of the JSON data"
+  |> StandardError
+  |> get_json_decode_error("")
+  |> should.equal(UnexpectedEndOfInput)
+}
+
+pub fn javascript_core_end_of_input_test() {
+  "JSON Parse error: Unexpected EOF"
+  |> StandardError
+  |> get_json_decode_error("")
+  |> should.equal(UnexpectedEndOfInput)
+}
+
+// === Unexpected byte tests === //
+pub fn chromium_unexpected_byte_test() {
+  "Unexpected token a in JSON at position 5"
+  |> StandardError
+  |> get_json_decode_error("{\"b\":a}")
+  |> should.equal(UnexpectedByte(byte: "0x61", position: 5))
+}
+
+pub fn spidermonkey_unexpected_byte_test() {
+  "JSON.parse: expected property name or '}' at line 1 column 6 of the JSON data"
+  |> StandardError
+  |> get_json_decode_error("{\"b\":a}")
+  |> should.equal(UnexpectedByte(byte: "0x61", position: 5))
+}
+
+pub fn javascript_core_unexpected_byte_test() {
+  "JSON Parse error: Unexpected identifier \"a\""
+  |> StandardError
+  |> get_json_decode_error("{\"b\":a}")
+  |> should.equal(UnexpectedByte(byte: "0x61", position: 0))
+}
+
+pub fn spidermonkey_multiline_unexpected_byte_test() {
+  "JSON.parse: expected property name or '}' at line 2 column 6 of the JSON data"
+  |> StandardError
+  |> get_json_decode_error("{\n\"b\": a\n}")
+  |> should.equal(UnexpectedByte(byte: "0x61", position: 7))
+
+  "JSON.parse: expected double-quoted property name at line 3 column 1 of the JSON data"
+  |> StandardError
+  |> get_json_decode_error("{\n\"b\": \"x\",\na\n}")
+  |> should.equal(UnexpectedByte(byte: "0x61", position: 12))
+}
+
+external fn get_json_decode_error(StandardError, String) -> DecodeError =
+  "./gleam_json_ffi.mjs" "getJsonDecodeError"