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/string/contains.wren

@@ -0,0 +1,8 @@
+io.write("".contains(""))              // expect: true
+io.write("anything".contains(""))      // expect: true
+io.write("something".contains("meth")) // expect: true
+io.write("something".contains("some")) // expect: true
+io.write("something".contains("ing"))  // expect: true
+io.write("something".contains("math")) // expect: false
+
+// TODO(bob): Passing non-string as argument.

test/string/count.wren

@@ -0,0 +1,2 @@
+io.write("".count)   // expect: 0
+io.write("a string".count) // expect: 8

test/string/equality.wren

@@ -0,0 +1,19 @@
+io.write("" == "")          // expect: true
+io.write("abcd" == "abcd")  // expect: true
+io.write("abcd" == "d")     // expect: false
+io.write("e" == "abcd")     // expect: false
+io.write("" == "abcd")      // expect: false
+
+// Not equal to other types.
+io.write("1" == 1)        // expect: false
+io.write("true" == true)  // expect: false
+
+io.write("" != "")          // expect: false
+io.write("abcd" != "abcd")  // expect: false
+io.write("abcd" != "d")     // expect: true
+io.write("e" != "abcd")     // expect: true
+io.write("" != "abcd")      // expect: true
+
+// Not equal to other types.
+io.write("1" != 1)        // expect: true
+io.write("true" != true)  // expect: true

test/string/escapes.wren

@@ -0,0 +1,8 @@
+// Escape characters.
+io.write("\"")     // expect: "
+io.write("\\")     // expect: \
+io.write("(\n)")   // expect: (
+                   // expect: )
+
+// TODO(bob): Non-printing escapes like \t.
+// TODO(bob): Unicode escape sequences.

test/string/literals.wren

@@ -0,0 +1,2 @@
+io.write("".count)   // expect: 0
+io.write("a string") // expect: a string

test/string/subscript.wren

@@ -0,0 +1,24 @@
+// Returns characters (as strings).
+io.write("abcd"[0]) // expect: a
+io.write("abcd"[1]) // expect: b
+io.write("abcd"[2]) // expect: c
+io.write("abcd"[3]) // expect: d
+
+// Allows indexing backwards from the end.
+io.write("abcd"[-4]) // expect: a
+io.write("abcd"[-3]) // expect: b
+io.write("abcd"[-2]) // expect: c
+io.write("abcd"[-1]) // expect: d
+
+// Handle out of bounds.
+// TODO(bob): Should halt the fiber or raise an error somehow.
+io.write("abcd"[4])  // expect: null
+io.write("abcd"[-5]) // expect: null
+
+// Handle wrong argument type.
+// TODO(bob): Should halt the fiber or raise an error somehow.
+io.write("abcd"[true]) // expect: null
+
+// Handle non-integer index.
+// TODO(bob): Should halt the fiber or raise an error somehow.
+io.write("abcd"[1.5]) // expect: null

test/string/to_string.wren

@@ -0,0 +1,2 @@
+io.write("".toString == "") // expect: true
+io.write("blah".toString == "blah") // expect: true

test/string/type.wren

@@ -0,0 +1,4 @@
+io.write("s" is String)      // expect: true
+io.write("s" is Object)      // expect: true
+io.write("s" is Num)         // expect: false
+io.write("s".type == String) // expect: true