diff --git a/xls/modules/zstd/BUILD b/xls/modules/zstd/BUILD
index f26a09d45e..6b72176806 100644
--- a/xls/modules/zstd/BUILD
+++ b/xls/modules/zstd/BUILD
@@ -153,16 +153,15 @@ cc_library(
         "@zstd//:decodecorpus",
     ],
     deps = [
+        "//xls/common:subprocess",
+        "//xls/common/file:filesystem",
+        "//xls/common/file:get_runfile_path",
+        "//xls/common/status:status_macros",
         "@com_google_absl//absl/algorithm:container",
-        "@com_google_absl//absl/status",
         "@com_google_absl//absl/status:statusor",
         "@com_google_absl//absl/strings",
         "@com_google_absl//absl/time",
         "@com_google_absl//absl/types:span",
-        "//xls/common:subprocess",
-        "//xls/common/file:filesystem",
-        "//xls/common/file:get_runfile_path",
-        "//xls/common/status:status_macros",
     ],
 )
 
@@ -210,11 +209,8 @@ cc_test(
         ":frame_header_test_dslx",
     ],
     shard_count = 50,
-    tags = ["manual"],
     deps = [
         ":data_generator",
-        "@com_google_absl//absl/container:flat_hash_map",
-        "@com_google_absl//absl/types:span",
         "//xls/common:xls_gunit_main",
         "//xls/common/file:filesystem",
         "//xls/common/file:get_runfile_path",
@@ -230,8 +226,10 @@ cc_test(
         "//xls/ir:bits",
         "//xls/ir:ir_test_base",
         "//xls/ir:value",
-        "@zstd",
+        "@com_google_absl//absl/container:flat_hash_map",
+        "@com_google_absl//absl/types:span",
         "@com_google_googletest//:gtest",
+        "@zstd",
     ],
 )
 
@@ -999,13 +997,8 @@ cc_test(
         ":zstd_dec_test.ir",
     ],
     shard_count = 50,
-    tags = ["manual"],
     deps = [
         ":data_generator",
-        "@com_google_absl//absl/container:flat_hash_map",
-        "@com_google_absl//absl/log",
-        "@com_google_absl//absl/status:statusor",
-        "@com_google_absl//absl/types:span",
         "//xls/common:xls_gunit_main",
         "//xls/common/file:filesystem",
         "//xls/common/file:get_runfile_path",
@@ -1020,8 +1013,12 @@ cc_test(
         "//xls/ir:ir_parser",
         "//xls/ir:value",
         "//xls/jit:jit_proc_runtime",
-        "@zstd",
+        "@com_google_absl//absl/container:flat_hash_map",
+        "@com_google_absl//absl/log",
+        "@com_google_absl//absl/status:statusor",
+        "@com_google_absl//absl/types:span",
         "@com_google_googletest//:gtest",
+        "@zstd",
     ],
 )
 
diff --git a/xls/modules/zstd/data_generator.cc b/xls/modules/zstd/data_generator.cc
index 81ffe95ed9..98b1eb4dba 100644
--- a/xls/modules/zstd/data_generator.cc
+++ b/xls/modules/zstd/data_generator.cc
@@ -60,9 +60,8 @@ static absl::StatusOr<SubprocessResult> CallDecodecorpus(
     absl::Span<const std::string> args,
     const std::optional<std::filesystem::path>& cwd = std::nullopt,
     std::optional<absl::Duration> timeout = std::nullopt) {
-  XLS_ASSIGN_OR_RETURN(
-      std::filesystem::path path,
-      xls::GetXlsRunfilePath("external/zstd/decodecorpus"));
+  XLS_ASSIGN_OR_RETURN(std::filesystem::path path,
+                       xls::GetXlsRunfilePath("external/zstd/decodecorpus"));
 
   std::vector<std::string> cmd = {path};
   cmd.insert(cmd.end(), args.begin(), args.end());
diff --git a/xls/modules/zstd/frame_header_test.cc b/xls/modules/zstd/frame_header_test.cc
index e78af06577..0eb8d5dbb8 100644
--- a/xls/modules/zstd/frame_header_test.cc
+++ b/xls/modules/zstd/frame_header_test.cc
@@ -24,12 +24,14 @@
 #include <utility>
 #include <vector>
 
-#include "gtest/gtest.h"
-#include "xls/common/fuzzing/fuzztest.h"
 #include "absl/container/flat_hash_map.h"
 #include "absl/types/span.h"
+#include "external/zstd/lib/zstd.h"
+#include "external/zstd/lib/zstd_errors.h"
+#include "gtest/gtest.h"
 #include "xls/common/file/filesystem.h"
 #include "xls/common/file/get_runfile_path.h"
+#include "xls/common/fuzzing/fuzztest.h"
 #include "xls/common/status/matchers.h"
 #include "xls/common/status/ret_check.h"
 #include "xls/dslx/create_import_data.h"
@@ -42,8 +44,6 @@
 #include "xls/ir/ir_test_base.h"
 #include "xls/ir/value.h"
 #include "xls/modules/zstd/data_generator.h"
-#include "external/zstd/lib/zstd.h"
-#include "external/zstd/lib/zstd_errors.h"
 
 namespace xls {
 namespace {
@@ -57,10 +57,22 @@ enum FrameHeaderStatus : uint8_t {
   UNSUPPORTED_WINDOW_SIZE
 };
 
-struct ZstdFrameHeader {
-  absl::Span<const uint8_t> kBuffer;
-  ZSTD_frameHeader kHeader;
-  size_t kResult;
+class ZstdFrameHeader {
+ public:
+  absl::Span<const uint8_t> buffer() const {
+    return absl::MakeConstSpan(buffer_);
+  }
+
+  ZSTD_frameHeader header() const { return header_; }
+
+  size_t result() const { return result_; }
+
+  ZstdFrameHeader(absl::Span<const uint8_t> buffer, ZSTD_frameHeader h,
+                  size_t r)
+      : header_(std::move(h)), result_(r) {
+    std::vector<uint8_t> v(buffer.begin(), buffer.end());
+    buffer_ = v;
+  }
   // Parse a frame header from an arbitrary buffer with the ZSTD library.
   static absl::StatusOr<ZstdFrameHeader> Parse(
       absl::Span<const uint8_t> buffer) {
@@ -69,8 +81,13 @@ struct ZstdFrameHeader {
     ZSTD_frameHeader zstd_fh;
     size_t result = ZSTD_getFrameHeader_advanced(
         &zstd_fh, buffer.data(), buffer.size(), ZSTD_f_zstd1_magicless);
-    return ZstdFrameHeader(buffer, zstd_fh, result);
+    return ZstdFrameHeader(buffer, std::move(zstd_fh), result);
   }
+
+ private:
+  std::vector<uint8_t> buffer_;
+  ZSTD_frameHeader header_;
+  size_t result_;
 };
 
 class FrameHeaderTest : public xls::IrTestBase {
@@ -113,7 +130,7 @@ class FrameHeaderTest : public xls::IrTestBase {
   // expected values.
   void RunAndExpectFrameHeader(const ZstdFrameHeader& zstd_frame_header) {
     // Extend buffer contents to 128 bits if necessary.
-    const absl::Span<const uint8_t>& buffer = zstd_frame_header.kBuffer;
+    const absl::Span<const uint8_t> buffer = zstd_frame_header.buffer();
     std::vector<uint8_t> buffer_extended(kDslxBufferSizeBytes, 0);
     absl::Span<const uint8_t> input_buffer;
     if (buffer.size() < kDslxBufferSizeBytes) {
@@ -124,8 +141,8 @@ class FrameHeaderTest : public xls::IrTestBase {
     }
 
     // Decide on the expected status
-    ZSTD_frameHeader zstd_fh = zstd_frame_header.kHeader;
-    size_t result = zstd_frame_header.kResult;
+    ZSTD_frameHeader zstd_fh = zstd_frame_header.header();
+    size_t result = zstd_frame_header.result();
     FrameHeaderStatus expected_status = FrameHeaderStatus::OK;
     if (result != 0) {
       if (ZSTD_isError(result)) {
diff --git a/xls/modules/zstd/zstd_dec_test.cc b/xls/modules/zstd/zstd_dec_test.cc
index 12fbaeb8ce..a428cb8187 100644
--- a/xls/modules/zstd/zstd_dec_test.cc
+++ b/xls/modules/zstd/zstd_dec_test.cc
@@ -33,11 +33,12 @@
 #include <utility>
 #include <vector>
 
-#include "gtest/gtest.h"
 #include "absl/container/flat_hash_map.h"
 #include "absl/log/log.h"
 #include "absl/status/statusor.h"
 #include "absl/types/span.h"
+#include "external/zstd/lib/zstd.h"
+#include "gtest/gtest.h"
 #include "xls/common/file/filesystem.h"
 #include "xls/common/file/get_runfile_path.h"
 #include "xls/common/status/matchers.h"
@@ -53,7 +54,6 @@
 #include "xls/ir/value.h"
 #include "xls/jit/jit_proc_runtime.h"
 #include "xls/modules/zstd/data_generator.h"
-#include "external/zstd/lib/zstd.h"
 
 namespace xls {
 namespace {