std: update test cases to reflect new packed struct semantics

lib/std/io/c_writer.zig

@@ -30,7 +30,7 @@ fn cWriterWrite(c_file: *std.c.FILE, bytes: []const u8) std.fs.File.WriteError!u
     }
 }
 
-test {
+test "C Writer" {
     if (!builtin.link_libc or builtin.os.tag == .wasi) return error.SkipZigTest;
 
     const filename = "tmp_io_test_file.txt";

lib/std/mem.zig

@@ -2831,6 +2831,8 @@ pub fn asBytes(ptr: anytype) AsBytesReturnType(@TypeOf(ptr)) {
 }
 
 test "asBytes" {
+    if (builtin.zig_backend == .stage1) return error.SkipZigTest;
+
     const deadbeef = @as(u32, 0xDEADBEEF);
     const deadbeef_bytes = switch (native_endian) {
         .Big => "\xDE\xAD\xBE\xEF",
@@ -2857,7 +2859,14 @@ test "asBytes" {
         .c = 0xDE,
         .d = 0xA1,
     };
-    try testing.expect(eql(u8, asBytes(&inst), "\xBE\xEF\xDE\xA1"));
+    switch (native_endian) {
+        .Little => {
+            try testing.expect(eql(u8, asBytes(&inst), "\xBE\xEF\xDE\xA1"));
+        },
+        .Big => {
+            try testing.expect(eql(u8, asBytes(&inst), "\xA1\xDE\xEF\xBE"));
+        },
+    }
 
     const ZST = struct {};
     const zero = ZST{};
@@ -2917,6 +2926,8 @@ pub fn bytesAsValue(comptime T: type, bytes: anytype) BytesAsValueReturnType(T,
 }
 
 test "bytesAsValue" {
+    if (builtin.zig_backend == .stage1) return error.SkipZigTest;
+
     const deadbeef = @as(u32, 0xDEADBEEF);
     const deadbeef_bytes = switch (native_endian) {
         .Big => "\xDE\xAD\xBE\xEF",
@@ -2948,7 +2959,10 @@ test "bytesAsValue" {
         .c = 0xDE,
         .d = 0xA1,
     };
-    const inst_bytes = "\xBE\xEF\xDE\xA1";
+    const inst_bytes = switch (native_endian) {
+        .Little => "\xBE\xEF\xDE\xA1",
+        .Big => "\xA1\xDE\xEF\xBE",
+    };
     const inst2 = bytesAsValue(S, inst_bytes);
     try testing.expect(meta.eql(inst, inst2.*));
 }
@@ -3115,6 +3129,8 @@ test "sliceAsBytes with sentinel slice" {
 }
 
 test "sliceAsBytes packed struct at runtime and comptime" {
+    if (builtin.zig_backend == .stage1) return error.SkipZigTest;
+
     const Foo = packed struct {
         a: u4,
         b: u4,
@@ -3124,16 +3140,8 @@ test "sliceAsBytes packed struct at runtime and comptime" {
             var foo: Foo = undefined;
             var slice = sliceAsBytes(@as(*[1]Foo, &foo)[0..1]);
             slice[0] = 0x13;
-            switch (native_endian) {
-                .Big => {
-                    try testing.expect(foo.a == 0x1);
-                    try testing.expect(foo.b == 0x3);
-                },
-                .Little => {
-                    try testing.expect(foo.a == 0x3);
-                    try testing.expect(foo.b == 0x1);
-                },
-            }
+            try testing.expect(foo.a == 0x3);
+            try testing.expect(foo.b == 0x1);
         }
     };
     try S.doTheTest();

lib/std/x/net/bpf.zig

@@ -706,12 +706,8 @@ fn expectFail(expected_error: anyerror, data: anytype, filter: []Insn) !void {
 }
 
 test "simulator coverage" {
-    const some_data: packed struct {
-        foo: u32,
-        bar: u8,
-    } = .{
-        .foo = mem.nativeToBig(u32, 0xaabbccdd),
-        .bar = 0x7f,
+    const some_data = [_]u8{
+        0xaa, 0xbb, 0xcc, 0xdd, 0x7f,
     };
 
     try expectPass(&some_data, &.{
@@ -764,7 +760,7 @@ test "simulator coverage" {
         // ld #len
         // fail if A != 5
         Insn.ld_len(),
-        Insn.jmp(.jeq, .{ .k = @sizeOf(@TypeOf(some_data)) }, 1, 0),
+        Insn.jmp(.jeq, .{ .k = some_data.len }, 1, 0),
         Insn.ret(.{ .k = 9 }),
         // ld #0
         // ld arc4random()