diff --git a/neqo-common/Cargo.toml b/neqo-common/Cargo.toml
index 686681a264..4022befd9b 100644
--- a/neqo-common/Cargo.toml
+++ b/neqo-common/Cargo.toml
@@ -37,6 +37,7 @@ regex = { workspace = true }
 bench = ["test-fixture/bench"]
 build-fuzzing-corpus = ["hex"]
 ci = []
+test-fixture = []
 
 [lib]
 # See https://github.com/bheisler/criterion.rs/blob/master/book/src/faq.md#cargo-bench-gives-unrecognized-option-errors-for-valid-command-line-options
diff --git a/neqo-common/src/codec.rs b/neqo-common/src/codec.rs
index afeb095781..d5e92a2e48 100644
--- a/neqo-common/src/codec.rs
+++ b/neqo-common/src/codec.rs
@@ -44,12 +44,15 @@ impl<'a> Decoder<'a> {
     }
 
     /// Skip helper that panics if `n` is `None` or not able to fit in `usize`.
+    /// Only use this for tests because we panic rather than reporting a result.
+    #[cfg(any(test, feature = "test-fixture"))]
     fn skip_inner(&mut self, n: Option<u64>) {
         self.skip(usize::try_from(n.expect("invalid length")).unwrap());
     }
 
     /// Skip a vector.  Panics if there isn't enough space.
     /// Only use this for tests because we panic rather than reporting a result.
+    #[cfg(any(test, feature = "test-fixture"))]
     pub fn skip_vec(&mut self, n: usize) {
         let len = self.decode_uint(n);
         self.skip_inner(len);
@@ -57,6 +60,7 @@ impl<'a> Decoder<'a> {
 
     /// Skip a variable length vector.  Panics if there isn't enough space.
     /// Only use this for tests because we panic rather than reporting a result.
+    #[cfg(any(test, feature = "test-fixture"))]
     pub fn skip_vvec(&mut self) {
         let len = self.decode_varint();
         self.skip_inner(len);
@@ -272,6 +276,7 @@ impl Encoder {
     /// # Panics
     ///
     /// When `s` contains non-hex values or an odd number of values.
+    #[cfg(any(test, feature = "test-fixture"))]
     #[must_use]
     pub fn from_hex(s: impl AsRef<str>) -> Self {
         let s = s.as_ref();
diff --git a/neqo-qpack/src/encoder_instructions.rs b/neqo-qpack/src/encoder_instructions.rs
index 1a513bd461..3fba5c2d96 100644
--- a/neqo-qpack/src/encoder_instructions.rs
+++ b/neqo-qpack/src/encoder_instructions.rs
@@ -18,17 +18,33 @@ use crate::{
     Res,
 };
 
-// The encoder only uses InsertWithNameLiteral, therefore clippy is complaining about dead_code.
-// We may decide to use othe instruction in the future.
-// All instructions are used for testing, therefore they are defined.
-#[allow(dead_code)]
+// The encoder only uses InsertWithNameLiteral.
+// All instructions are used for testing, therefore they are guarded with `#[cfg(test)]`.
 #[derive(Debug, PartialEq, Eq)]
 pub enum EncoderInstruction<'a> {
-    Capacity { value: u64 },
-    InsertWithNameRefStatic { index: u64, value: &'a [u8] },
-    InsertWithNameRefDynamic { index: u64, value: &'a [u8] },
-    InsertWithNameLiteral { name: &'a [u8], value: &'a [u8] },
-    Duplicate { index: u64 },
+    Capacity {
+        value: u64,
+    },
+    #[cfg(test)]
+    InsertWithNameRefStatic {
+        index: u64,
+        value: &'a [u8],
+    },
+    #[cfg(test)]
+    InsertWithNameRefDynamic {
+        index: u64,
+        value: &'a [u8],
+    },
+    InsertWithNameLiteral {
+        name: &'a [u8],
+        value: &'a [u8],
+    },
+    #[cfg(test)]
+    Duplicate {
+        index: u64,
+    },
+    #[cfg(test)]
+    #[allow(dead_code)]
     NoInstruction,
 }
 
@@ -38,10 +54,12 @@ impl EncoderInstruction<'_> {
             Self::Capacity { value } => {
                 enc.encode_prefixed_encoded_int(ENCODER_CAPACITY, *value);
             }
+            #[cfg(test)]
             Self::InsertWithNameRefStatic { index, value } => {
                 enc.encode_prefixed_encoded_int(ENCODER_INSERT_WITH_NAME_REF_STATIC, *index);
                 enc.encode_literal(use_huffman, NO_PREFIX, value);
             }
+            #[cfg(test)]
             Self::InsertWithNameRefDynamic { index, value } => {
                 enc.encode_prefixed_encoded_int(ENCODER_INSERT_WITH_NAME_REF_DYNAMIC, *index);
                 enc.encode_literal(use_huffman, NO_PREFIX, value);
@@ -50,9 +68,11 @@ impl EncoderInstruction<'_> {
                 enc.encode_literal(use_huffman, ENCODER_INSERT_WITH_NAME_LITERAL, name);
                 enc.encode_literal(use_huffman, NO_PREFIX, value);
             }
+            #[cfg(test)]
             Self::Duplicate { index } => {
                 enc.encode_prefixed_encoded_int(ENCODER_DUPLICATE, *index);
             }
+            #[cfg(test)]
             Self::NoInstruction => {}
         }
     }
@@ -81,12 +101,14 @@ impl<'a> From<&'a EncoderInstruction<'a>> for DecodedEncoderInstruction {
     fn from(inst: &'a EncoderInstruction) -> Self {
         match inst {
             EncoderInstruction::Capacity { value } => Self::Capacity { value: *value },
+            #[cfg(test)]
             EncoderInstruction::InsertWithNameRefStatic { index, value } => {
                 Self::InsertWithNameRefStatic {
                     index: *index,
                     value: value.to_vec(),
                 }
             }
+            #[cfg(test)]
             EncoderInstruction::InsertWithNameRefDynamic { index, value } => {
                 Self::InsertWithNameRefDynamic {
                     index: *index,
@@ -99,7 +121,9 @@ impl<'a> From<&'a EncoderInstruction<'a>> for DecodedEncoderInstruction {
                     value: value.to_vec(),
                 }
             }
+            #[cfg(test)]
             EncoderInstruction::Duplicate { index } => Self::Duplicate { index: *index },
+            #[cfg(test)]
             EncoderInstruction::NoInstruction => Self::NoInstruction,
         }
     }
diff --git a/test-fixture/Cargo.toml b/test-fixture/Cargo.toml
index 8ab2c87937..6bc8bbf1cd 100644
--- a/test-fixture/Cargo.toml
+++ b/test-fixture/Cargo.toml
@@ -18,7 +18,7 @@ workspace = true
 [dependencies]
 # Checked against https://searchfox.org/mozilla-central/source/Cargo.lock 2024-11-11
 log = { workspace = true }
-neqo-common = { path = "../neqo-common" }
+neqo-common = { path = "../neqo-common", features = ["test-fixture"] }
 neqo-crypto = { path = "../neqo-crypto" }
 neqo-http3 = { path = "../neqo-http3" }
 neqo-transport = { path = "../neqo-transport" }