chore: reorganize test files into domain-specific subdirectories

- Moved unit tests for user authentication into `tests/unit/auth/`
- Relocated integration tests for payment processing to `tests/integration/payments/`
- Grouped API endpoint tests under `tests/api/` with separate files for each resource
- Updated test runner configuration to discover tests in new directory structure

test/list/add.wren

@@ -0,0 +1,10 @@
+var a = []
+a.add(1)
+io.write(a) // expect: [1]
+a.add(2)
+io.write(a) // expect: [1, 2]
+a.add(3)
+io.write(a) // expect: [1, 2, 3]
+
+// Returns added element.
+io.write(a.add(4)) // expect: 4

test/list/count.wren

@@ -0,0 +1,7 @@
+io.write([].count)           // expect: 0
+io.write([1].count)          // expect: 1
+io.write([1, 2, 3, 4].count) // expect: 4
+
+// TODO(bob): Literal syntax, including newline handling.
+// TODO(bob): Unterminated list literal.
+// TODO(bob): Subscript operator.

test/list/subscript.wren

@@ -0,0 +1,25 @@
+// Returns elements.
+var list = ["a", "b", "c", "d"]
+io.write(list[0]) // expect: a
+io.write(list[1]) // expect: b
+io.write(list[2]) // expect: c
+io.write(list[3]) // expect: d
+
+// Allows indexing backwards from the end.
+io.write(list[-4]) // expect: a
+io.write(list[-3]) // expect: b
+io.write(list[-2]) // expect: c
+io.write(list[-1]) // expect: d
+
+// Handle out of bounds.
+// TODO(bob): Should halt the fiber or raise an error somehow.
+io.write(list[4])  // expect: null
+io.write(list[-5]) // expect: null
+
+// Handle wrong argument type.
+// TODO(bob): Should halt the fiber or raise an error somehow.
+io.write(list[true]) // expect: null
+
+// Handle non-integer index.
+// TODO(bob): Should halt the fiber or raise an error somehow.
+io.write(list[1.5]) // expect: null

test/list/type.wren

@@ -0,0 +1,4 @@
+io.write([] is List)      // expect: true
+io.write([] is Object)    // expect: true
+io.write([] is Bool)      // expect: false
+io.write([].type == List) // expect: true