internal/pipewire: move test data to files

These get very big later on, and would be painful to represent as the compound literal.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/pipewire/header_test.go

@@ -11,33 +11,17 @@ func TestHeader(t *testing.T) {
 	t.Parallel()
 
 	encodingTestCases[pipewire.Header, *pipewire.Header]{
-		{"PW_CORE_METHOD_HELLO", []byte{
-			// Id
-			0, 0, 0, 0,
-			// size
-			0x18, 0, 0,
-			// opcode
-			1,
-			// seq
-			0, 0, 0, 0,
-			// n_fds
-			0, 0, 0, 0,
-		}, pipewire.Header{ID: pipewire.PW_ID_CORE, Opcode: pipewire.PW_CORE_METHOD_HELLO,
-			Size: 0x18, Sequence: 0, FileCount: 0}, nil},
+		{"PW_CORE_METHOD_HELLO", []byte(sendmsg00Message00Header), pipewire.Header{
+			ID:     pipewire.PW_ID_CORE,
+			Opcode: pipewire.PW_CORE_METHOD_HELLO,
+			Size:   0x18, Sequence: 0, FileCount: 0,
+		}, nil},
 
-		{"PW_CLIENT_METHOD_UPDATE_PROPERTIES", []byte{
-			// Id
-			1, 0, 0, 0,
-			// size
-			0, 6, 0,
-			// opcode
-			2,
-			// seq
-			1, 0, 0, 0,
-			// n_fds
-			0, 0, 0, 0,
-		}, pipewire.Header{ID: pipewire.PW_ID_CLIENT, Opcode: pipewire.PW_CLIENT_METHOD_UPDATE_PROPERTIES,
-			Size: 0x600, Sequence: 1, FileCount: 0}, nil},
+		{"PW_CLIENT_METHOD_UPDATE_PROPERTIES", []byte(sendmsg00Message01Header), pipewire.Header{
+			ID:     pipewire.PW_ID_CLIENT,
+			Opcode: pipewire.PW_CLIENT_METHOD_UPDATE_PROPERTIES,
+			Size:   0x600, Sequence: 1, FileCount: 0,
+		}, nil},
 
 		{"PW_SECURITY_CONTEXT_METHOD_CREATE", []byte{
 			// Id