Reorganize tests and benchmark scripts.

Mainly to get rid of one top level directory. But this will
also be useful when there are tests of the embedding API.

test/core/function/arity.wren

@@ -0,0 +1,5 @@
+IO.print(new Fn {}.arity) // expect: 0
+IO.print(new Fn {|a| a}.arity) // expect: 1
+IO.print(new Fn {|a, b| a}.arity) // expect: 2
+IO.print(new Fn {|a, b, c| a}.arity) // expect: 3
+IO.print(new Fn {|a, b, c, d| a}.arity) // expect: 4

test/core/function/call_extra_arguments.wren

@@ -0,0 +1,16 @@
+var f0 = new Fn { IO.print("zero") }
+var f1 = new Fn {|a| IO.print("one ", a) }
+var f2 = new Fn {|a, b| IO.print("two ", a, " ", b) }
+var f3 = new Fn {|a, b, c| IO.print("three ", a, " ", b, " ", c) }
+
+f0.call("a") // expect: zero
+f0.call("a", "b") // expect: zero
+
+f1.call("a", "b") // expect: one a
+f1.call("a", "b", "c") // expect: one a
+
+f2.call("a", "b", "c") // expect: two a b
+f2.call("a", "b", "c", "d") // expect: two a b
+
+f3.call("a", "b", "c", "d") // expect: three a b c
+f3.call("a", "b", "c", "d", "e") // expect: three a b c

test/core/function/call_missing_arguments.wren

@@ -0,0 +1,2 @@
+var f2 = new Fn {|a, b| IO.print(a, b) }
+f2.call("a") // expect runtime error: Function expects more arguments.

test/core/function/equality.wren

@@ -0,0 +1,16 @@
+// Not structurally equal.
+IO.print(new Fn { 123 } == new Fn { 123 })  // expect: false
+IO.print(new Fn { 123 } != new Fn { 123 })  // expect: true
+
+// Not equal to other types.
+IO.print(new Fn { 123 } == 1)         // expect: false
+IO.print(new Fn { 123 } == false)     // expect: false
+IO.print(new Fn { 123 } == "fn 123")  // expect: false
+IO.print(new Fn { 123 } != 1)         // expect: true
+IO.print(new Fn { 123 } != false)     // expect: true
+IO.print(new Fn { 123 } != "fn 123")  // expect: true
+
+// Equal by identity.
+var f = new Fn { 123 }
+IO.print(f == f) // expect: true
+IO.print(f != f) // expect: false

test/core/function/new_wrong_arg_type.wren

@@ -0,0 +1 @@
+new Fn(3) // expect runtime error: Argument must be a function.

test/core/function/to_string.wren

@@ -0,0 +1 @@
+IO.print(new Fn {}) // expect: <fn>

test/core/function/type.wren

@@ -0,0 +1,4 @@
+IO.print(new Fn { 0 } is Fn)      // expect: true
+IO.print(new Fn { 0 } is Object)  // expect: true
+IO.print(new Fn { 0 } is String)  // expect: false
+IO.print(new Fn { 0 }.type == Fn) // expect: true