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/class/ctor_named.wren

@@ -0,0 +1,20 @@
+class Foo {
+  this bar { io.write("this bar") }
+  this baz { io.write("this baz") }
+  this bar(arg) { io.write("this bar " + arg) }
+
+  toString { "Foo" }
+}
+
+// Different names.
+Foo.bar // expect: this bar
+Foo.baz // expect: this baz
+
+// Can overload by arity.
+Foo.bar // expect: this bar
+Foo.bar("one") // expect: this bar one
+
+// Returns the new instance.
+var foo = Foo.bar // expect: this bar
+io.write(foo is Foo) // expect: true
+io.write(foo.toString) // expect: Foo

test/class/equality.wren

@@ -0,0 +1,13 @@
+io.write(Num == Num)  // expect: true
+io.write(Num == Bool) // expect: false
+
+// Not equal to other types.
+io.write(Num == 123)  // expect: false
+io.write(Num == true) // expect: false
+
+io.write(Num != Num)  // expect: false
+io.write(Num != Bool) // expect: true
+
+// Not equal to other types.
+io.write(Num != 123)  // expect: true
+io.write(Num != true) // expect: true

test/class/inheritance.wren

@@ -0,0 +1,27 @@
+class Foo {
+  methodOnFoo { io.write("foo") }
+  method(a) { io.write("foo") }
+  method(a, b, c) { io.write("foo") }
+}
+
+class Bar is Foo {
+  methodOnBar { io.write("bar") }
+  method(a, b) { io.write("bar") }
+  method(a, b, c, d) { io.write("bar") }
+}
+
+var bar = Bar.new
+bar.methodOnFoo // expect: foo
+bar.methodOnBar // expect: bar
+
+// Methods with different arity do not shadow each other.
+bar.method(1) // expect: foo
+bar.method(1, 2) // expect: bar
+bar.method(1, 2, 3) // expect: foo
+bar.method(1, 2, 3, 4) // expect: bar
+
+// TODO(bob): Overriding (or BETA-style refining?).
+// TODO(bob): Private fields.
+// TODO(bob): Super (or inner) calls.
+// TODO(bob): Grammar for what expressions can follow "is".
+// TODO(bob): Prevent extending built-in types.

test/class/new.wren

@@ -0,0 +1,4 @@
+class Foo {}
+
+var foo = Foo.new
+io.write(foo is Foo) // expect: true

test/class/syntax.wren

@@ -0,0 +1,7 @@
+// Empty body.
+class A {}
+
+// Newline body.
+class B {
+
+}