parser: port formatting, declaration, fn attribute tests

Port tests:
- "preserve spacing"
- "return types"
- "imports"
- "global declarations"
- "extern declaration"
- "function attributes"
- "nested pointers with ** tokens"
- "test declaration"

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

parser_test.zig

@@ -3151,6 +3151,104 @@ test "zig fmt: first line comment in struct initializer" {
     );
 }
 
+test "zig fmt: preserve spacing" {
+    try testCanonical(
+        \\const std = @import("std");
+        \\
+        \\pub fn main() !void {
+        \\    var stdout_file = std.lol.abcd;
+        \\    var stdout_file = std.lol.abcd;
+        \\
+        \\    var stdout_file = std.lol.abcd;
+        \\    var stdout_file = std.lol.abcd;
+        \\}
+        \\
+    );
+}
+
+test "zig fmt: return types" {
+    try testCanonical(
+        \\pub fn main() !void {}
+        \\pub fn main() FooBar {}
+        \\pub fn main() i32 {}
+        \\
+    );
+}
+
+test "zig fmt: imports" {
+    try testCanonical(
+        \\const std = @import("std");
+        \\const std = @import();
+        \\
+    );
+}
+
+test "zig fmt: global declarations" {
+    try testCanonical(
+        \\const a = b;
+        \\pub const a = b;
+        \\var a = b;
+        \\pub var a = b;
+        \\const a: i32 = b;
+        \\pub const a: i32 = b;
+        \\var a: i32 = b;
+        \\pub var a: i32 = b;
+        \\extern const a: i32 = b;
+        \\pub extern const a: i32 = b;
+        \\extern var a: i32 = b;
+        \\pub extern var a: i32 = b;
+        \\extern "a" const a: i32 = b;
+        \\pub extern "a" const a: i32 = b;
+        \\extern "a" var a: i32 = b;
+        \\pub extern "a" var a: i32 = b;
+        \\
+    );
+}
+
+test "zig fmt: extern declaration" {
+    try testCanonical(
+        \\extern var foo: c_int;
+        \\
+    );
+}
+
+test "zig fmt: function attributes" {
+    try testCanonical(
+        \\export fn foo() void {}
+        \\pub export fn foo() void {}
+        \\extern fn foo() void;
+        \\pub extern fn foo() void;
+        \\extern "c" fn foo() void;
+        \\pub extern "c" fn foo() void;
+        \\noinline fn foo() void {}
+        \\pub noinline fn foo() void {}
+        \\
+    );
+}
+
+test "zig fmt: nested pointers with ** tokens" {
+    try testCanonical(
+        \\const x: *u32 = undefined;
+        \\const x: **u32 = undefined;
+        \\const x: ***u32 = undefined;
+        \\const x: ****u32 = undefined;
+        \\const x: *****u32 = undefined;
+        \\const x: ******u32 = undefined;
+        \\const x: *******u32 = undefined;
+        \\
+    );
+}
+
+test "zig fmt: test declaration" {
+    try testCanonical(
+        \\test "test name" {
+        \\    const a = 1;
+        \\    var b = 1;
+        \\}
+        \\
+    );
+}
+
 test "zig fmt: error set declaration" {
     try testCanonical(
         \\const E = error{