diff --git a/test_suite/tests/test_de.rs b/test_suite/tests/test_de.rs
index 9bfde818..a8cccd89 100644
--- a/test_suite/tests/test_de.rs
+++ b/test_suite/tests/test_de.rs
@@ -21,7 +21,7 @@ use std::sync::atomic::{
     AtomicUsize, Ordering,
 };
 use std::sync::{Arc, Weak as ArcWeak};
-use std::time::{Duration, SystemTime, UNIX_EPOCH};
+use std::time::{Duration, UNIX_EPOCH};
 
 #[cfg(target_arch = "x86_64")]
 use std::sync::atomic::{AtomicI64, AtomicU64};
@@ -29,7 +29,7 @@ use std::sync::atomic::{AtomicI64, AtomicU64};
 use fnv::FnvHasher;
 use serde::de::DeserializeOwned;
 use serde::{Deserialize, Deserializer};
-use serde_test::{assert_de_tokens, assert_de_tokens_error, Configure, Token};
+use serde_test::{assert_de_tokens, Configure, Token};
 
 #[macro_use]
 mod macros;
@@ -53,14 +53,6 @@ struct Struct {
     c: i32,
 }
 
-#[derive(PartialEq, Debug, Deserialize)]
-#[serde(deny_unknown_fields)]
-struct StructDenyUnknown {
-    a: i32,
-    #[serde(skip_deserializing)]
-    b: i32,
-}
-
 #[derive(PartialEq, Debug, Deserialize)]
 #[serde(default)]
 struct StructDefault<T> {
@@ -129,13 +121,6 @@ enum Enum {
     SimpleWithSkipped(#[serde(skip_deserializing)] NotDeserializable),
 }
 
-#[derive(PartialEq, Debug, Deserialize)]
-enum EnumSkipAll {
-    #[allow(dead_code)]
-    #[serde(skip_deserializing)]
-    Skipped,
-}
-
 #[derive(PartialEq, Debug, Deserialize)]
 enum EnumOther {
     Unit,
@@ -167,21 +152,6 @@ fn test<'de>(value: impl Deserialize<'de> + PartialEq + Debug, tokens: &'de [Tok
     assert_de_tokens_ignore(tokens);
 }
 
-macro_rules! declare_error_tests {
-    ($(
-        $(#[$cfg:meta])*
-        $name:ident<$target:ty> { $tokens:expr, $expected:expr, }
-    )+) => {
-        $(
-            $(#[$cfg])*
-            #[test]
-            fn $name() {
-                assert_de_tokens_error::<$target>($tokens, $expected);
-            }
-        )+
-    }
-}
-
 #[derive(Debug)]
 struct SkipPartialEq<T>(T);
 
@@ -1705,36 +1675,6 @@ fn test_cstr() {
     );
 }
 
-#[test]
-fn test_cstr_internal_null() {
-    assert_de_tokens_error::<Box<CStr>>(
-        &[Token::Bytes(b"a\0c")],
-        "nul byte found in provided data at position: 1",
-    );
-}
-
-#[test]
-fn test_cstr_internal_null_end() {
-    assert_de_tokens_error::<Box<CStr>>(
-        &[Token::Bytes(b"ac\0")],
-        "nul byte found in provided data at position: 2",
-    );
-}
-
-#[cfg(feature = "unstable")]
-#[test]
-fn test_never_type() {
-    assert_de_tokens_error::<!>(&[], "cannot deserialize `!`");
-
-    assert_de_tokens_error::<Result<u8, !>>(
-        &[Token::NewtypeVariant {
-            name: "Result",
-            variant: "Err",
-        }],
-        "cannot deserialize `!`",
-    );
-}
-
 #[test]
 fn test_atomics() {
     fn test<L, A, T>(load: L, val: T, token: Token)
@@ -1773,286 +1713,3 @@ fn test_atomics() {
         test(AtomicU64::load, 8589934592u64, Token::U64(8589934592));
     }
 }
-
-declare_error_tests! {
-    test_unknown_field<StructDenyUnknown> {
-        &[
-            Token::Struct { name: "StructDenyUnknown", len: 1 },
-                Token::Str("a"),
-                Token::I32(0),
-
-                Token::Str("d"),
-        ],
-        "unknown field `d`, expected `a`",
-    }
-    test_skipped_field_is_unknown<StructDenyUnknown> {
-        &[
-            Token::Struct { name: "StructDenyUnknown", len: 1 },
-                Token::Str("b"),
-        ],
-        "unknown field `b`, expected `a`",
-    }
-    test_skip_all_deny_unknown<StructSkipAllDenyUnknown> {
-        &[
-            Token::Struct { name: "StructSkipAllDenyUnknown", len: 0 },
-                Token::Str("a"),
-        ],
-        "unknown field `a`, there are no fields",
-    }
-    test_unknown_variant<Enum> {
-        &[
-            Token::UnitVariant { name: "Enum", variant: "Foo" },
-        ],
-        "unknown variant `Foo`, expected one of `Unit`, `Simple`, `Seq`, `Map`, `SimpleWithSkipped`",
-    }
-    test_enum_skipped_variant<Enum> {
-        &[
-            Token::UnitVariant { name: "Enum", variant: "Skipped" },
-        ],
-        "unknown variant `Skipped`, expected one of `Unit`, `Simple`, `Seq`, `Map`, `SimpleWithSkipped`",
-    }
-    test_enum_skip_all<EnumSkipAll> {
-        &[
-            Token::UnitVariant { name: "EnumSkipAll", variant: "Skipped" },
-        ],
-        "unknown variant `Skipped`, there are no variants",
-    }
-    test_duplicate_field_struct<Struct> {
-        &[
-            Token::Map { len: Some(3) },
-                Token::Str("a"),
-                Token::I32(1),
-
-                Token::Str("a"),
-        ],
-        "duplicate field `a`",
-    }
-    test_duplicate_field_enum<Enum> {
-        &[
-            Token::StructVariant { name: "Enum", variant: "Map", len: 3 },
-                Token::Str("a"),
-                Token::I32(1),
-
-                Token::Str("a"),
-        ],
-        "duplicate field `a`",
-    }
-    test_enum_out_of_range<Enum> {
-        &[
-            Token::Enum { name: "Enum" },
-            Token::U32(5),
-            Token::Unit,
-        ],
-        "invalid value: integer `5`, expected variant index 0 <= i < 5",
-    }
-    test_short_tuple<(u8, u8, u8)> {
-        &[
-            Token::Tuple { len: 1 },
-            Token::U8(1),
-            Token::TupleEnd,
-        ],
-        "invalid length 1, expected a tuple of size 3",
-    }
-    test_short_array<[u8; 3]> {
-        &[
-            Token::Seq { len: Some(1) },
-            Token::U8(1),
-            Token::SeqEnd,
-        ],
-        "invalid length 1, expected an array of length 3",
-    }
-    test_cstring_internal_null<CString> {
-        &[
-            Token::Bytes(b"a\0c"),
-        ],
-        "nul byte found in provided data at position: 1",
-    }
-    test_cstring_internal_null_end<CString> {
-        &[
-            Token::Bytes(b"ac\0"),
-        ],
-        "nul byte found in provided data at position: 2",
-    }
-    test_unit_from_empty_seq<()> {
-        &[
-            Token::Seq { len: Some(0) },
-            Token::SeqEnd,
-        ],
-        "invalid type: sequence, expected unit",
-    }
-    test_unit_from_empty_seq_without_len<()> {
-        &[
-            Token::Seq { len: None },
-            Token::SeqEnd,
-        ],
-        "invalid type: sequence, expected unit",
-    }
-    test_unit_from_tuple_struct<()> {
-        &[
-            Token::TupleStruct { name: "Anything", len: 0 },
-            Token::TupleStructEnd,
-        ],
-        "invalid type: sequence, expected unit",
-    }
-    test_string_from_unit<String> {
-        &[
-            Token::Unit,
-        ],
-        "invalid type: unit value, expected a string",
-    }
-    test_btreeset_from_unit<BTreeSet<isize>> {
-        &[
-            Token::Unit,
-        ],
-        "invalid type: unit value, expected a sequence",
-    }
-    test_btreeset_from_unit_struct<BTreeSet<isize>> {
-        &[
-            Token::UnitStruct { name: "Anything" },
-        ],
-        "invalid type: unit value, expected a sequence",
-    }
-    test_hashset_from_unit<HashSet<isize>> {
-        &[
-            Token::Unit,
-        ],
-        "invalid type: unit value, expected a sequence",
-    }
-    test_hashset_from_unit_struct<HashSet<isize>> {
-        &[
-            Token::UnitStruct { name: "Anything" },
-        ],
-        "invalid type: unit value, expected a sequence",
-    }
-    test_vec_from_unit<Vec<isize>> {
-        &[
-            Token::Unit,
-        ],
-        "invalid type: unit value, expected a sequence",
-    }
-    test_vec_from_unit_struct<Vec<isize>> {
-        &[
-            Token::UnitStruct { name: "Anything" },
-        ],
-        "invalid type: unit value, expected a sequence",
-    }
-    test_zero_array_from_unit<[isize; 0]> {
-        &[
-            Token::Unit,
-        ],
-        "invalid type: unit value, expected an empty array",
-    }
-    test_zero_array_from_unit_struct<[isize; 0]> {
-        &[
-            Token::UnitStruct { name: "Anything" },
-        ],
-        "invalid type: unit value, expected an empty array",
-    }
-    test_btreemap_from_unit<BTreeMap<isize, isize>> {
-        &[
-            Token::Unit,
-        ],
-        "invalid type: unit value, expected a map",
-    }
-    test_btreemap_from_unit_struct<BTreeMap<isize, isize>> {
-        &[
-            Token::UnitStruct { name: "Anything" },
-        ],
-        "invalid type: unit value, expected a map",
-    }
-    test_hashmap_from_unit<HashMap<isize, isize>> {
-        &[
-            Token::Unit,
-        ],
-        "invalid type: unit value, expected a map",
-    }
-    test_hashmap_from_unit_struct<HashMap<isize, isize>> {
-        &[
-            Token::UnitStruct { name: "Anything" },
-        ],
-        "invalid type: unit value, expected a map",
-    }
-    test_bool_from_string<bool> {
-        &[
-            Token::Str("false"),
-        ],
-        "invalid type: string \"false\", expected a boolean",
-    }
-    test_number_from_string<isize> {
-        &[
-            Token::Str("1"),
-        ],
-        "invalid type: string \"1\", expected isize",
-    }
-    test_integer_from_float<isize> {
-        &[
-            Token::F32(0.0),
-        ],
-        "invalid type: floating point `0`, expected isize",
-    }
-    test_unit_struct_from_seq<UnitStruct> {
-        &[
-            Token::Seq { len: Some(0) },
-            Token::SeqEnd,
-        ],
-        "invalid type: sequence, expected unit struct UnitStruct",
-    }
-    test_wrapping_overflow<Wrapping<u16>> {
-        &[
-            Token::U32(65_536),
-        ],
-        "invalid value: integer `65536`, expected u16",
-    }
-    test_duration_overflow_seq<Duration> {
-        &[
-            Token::Seq { len: Some(2) },
-                Token::U64(u64::max_value()),
-                Token::U32(1_000_000_000),
-            Token::SeqEnd,
-        ],
-        "overflow deserializing Duration",
-    }
-    test_duration_overflow_struct<Duration> {
-        &[
-            Token::Struct { name: "Duration", len: 2 },
-                Token::Str("secs"),
-                Token::U64(u64::max_value()),
-
-                Token::Str("nanos"),
-                Token::U32(1_000_000_000),
-            Token::StructEnd,
-        ],
-        "overflow deserializing Duration",
-    }
-    test_systemtime_overflow_seq<SystemTime> {
-        &[
-            Token::Seq { len: Some(2) },
-                Token::U64(u64::max_value()),
-                Token::U32(1_000_000_000),
-            Token::SeqEnd,
-        ],
-        "overflow deserializing SystemTime epoch offset",
-    }
-    test_systemtime_overflow_struct<SystemTime> {
-        &[
-            Token::Struct { name: "SystemTime", len: 2 },
-                Token::Str("secs_since_epoch"),
-                Token::U64(u64::max_value()),
-
-                Token::Str("nanos_since_epoch"),
-                Token::U32(1_000_000_000),
-            Token::StructEnd,
-        ],
-        "overflow deserializing SystemTime epoch offset",
-    }
-    #[cfg(systemtime_checked_add)]
-    test_systemtime_overflow<SystemTime> {
-        &[
-            Token::Seq { len: Some(2) },
-                Token::U64(u64::max_value()),
-                Token::U32(0),
-            Token::SeqEnd,
-        ],
-        "overflow deserializing SystemTime",
-    }
-}
diff --git a/test_suite/tests/test_de_error.rs b/test_suite/tests/test_de_error.rs
new file mode 100644
index 00000000..b8b732bf
--- /dev/null
+++ b/test_suite/tests/test_de_error.rs
@@ -0,0 +1,389 @@
+#![allow(clippy::empty_enum)]
+#![cfg_attr(feature = "unstable", feature(never_type))]
+
+use serde::Deserialize;
+use serde_test::{assert_de_tokens_error, Token};
+use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
+use std::ffi::{CStr, CString};
+use std::num::Wrapping;
+use std::time::{Duration, SystemTime};
+
+#[derive(Copy, Clone, PartialEq, Debug, Deserialize)]
+struct UnitStruct;
+
+#[derive(PartialEq, Debug, Deserialize)]
+struct Struct {
+    a: i32,
+    b: i32,
+    #[serde(skip_deserializing)]
+    c: i32,
+}
+
+#[derive(PartialEq, Debug, Deserialize)]
+#[serde(deny_unknown_fields)]
+struct StructDenyUnknown {
+    a: i32,
+    #[serde(skip_deserializing)]
+    b: i32,
+}
+
+#[derive(PartialEq, Debug, Deserialize)]
+#[serde(deny_unknown_fields)]
+struct StructSkipAllDenyUnknown {
+    #[serde(skip_deserializing)]
+    a: i32,
+}
+
+#[derive(Default, PartialEq, Debug)]
+struct NotDeserializable;
+
+#[derive(PartialEq, Debug, Deserialize)]
+enum Enum {
+    #[allow(dead_code)]
+    #[serde(skip_deserializing)]
+    Skipped,
+    Unit,
+    Simple(i32),
+    Seq(i32, i32, i32),
+    Map {
+        a: i32,
+        b: i32,
+        c: i32,
+    },
+    SimpleWithSkipped(#[serde(skip_deserializing)] NotDeserializable),
+}
+
+#[derive(PartialEq, Debug, Deserialize)]
+enum EnumSkipAll {
+    #[allow(dead_code)]
+    #[serde(skip_deserializing)]
+    Skipped,
+}
+
+macro_rules! declare_error_tests {
+    ($(
+        $(#[$cfg:meta])*
+        $name:ident<$target:ty> { $tokens:expr, $expected:expr, }
+    )+) => {
+        $(
+            $(#[$cfg])*
+            #[test]
+            fn $name() {
+                assert_de_tokens_error::<$target>($tokens, $expected);
+            }
+        )+
+    }
+}
+
+declare_error_tests! {
+    test_unknown_field<StructDenyUnknown> {
+        &[
+            Token::Struct { name: "StructDenyUnknown", len: 1 },
+                Token::Str("a"),
+                Token::I32(0),
+
+                Token::Str("d"),
+        ],
+        "unknown field `d`, expected `a`",
+    }
+    test_skipped_field_is_unknown<StructDenyUnknown> {
+        &[
+            Token::Struct { name: "StructDenyUnknown", len: 1 },
+                Token::Str("b"),
+        ],
+        "unknown field `b`, expected `a`",
+    }
+    test_skip_all_deny_unknown<StructSkipAllDenyUnknown> {
+        &[
+            Token::Struct { name: "StructSkipAllDenyUnknown", len: 0 },
+                Token::Str("a"),
+        ],
+        "unknown field `a`, there are no fields",
+    }
+    test_unknown_variant<Enum> {
+        &[
+            Token::UnitVariant { name: "Enum", variant: "Foo" },
+        ],
+        "unknown variant `Foo`, expected one of `Unit`, `Simple`, `Seq`, `Map`, `SimpleWithSkipped`",
+    }
+    test_enum_skipped_variant<Enum> {
+        &[
+            Token::UnitVariant { name: "Enum", variant: "Skipped" },
+        ],
+        "unknown variant `Skipped`, expected one of `Unit`, `Simple`, `Seq`, `Map`, `SimpleWithSkipped`",
+    }
+    test_enum_skip_all<EnumSkipAll> {
+        &[
+            Token::UnitVariant { name: "EnumSkipAll", variant: "Skipped" },
+        ],
+        "unknown variant `Skipped`, there are no variants",
+    }
+    test_duplicate_field_struct<Struct> {
+        &[
+            Token::Map { len: Some(3) },
+                Token::Str("a"),
+                Token::I32(1),
+
+                Token::Str("a"),
+        ],
+        "duplicate field `a`",
+    }
+    test_duplicate_field_enum<Enum> {
+        &[
+            Token::StructVariant { name: "Enum", variant: "Map", len: 3 },
+                Token::Str("a"),
+                Token::I32(1),
+
+                Token::Str("a"),
+        ],
+        "duplicate field `a`",
+    }
+    test_enum_out_of_range<Enum> {
+        &[
+            Token::Enum { name: "Enum" },
+            Token::U32(5),
+            Token::Unit,
+        ],
+        "invalid value: integer `5`, expected variant index 0 <= i < 5",
+    }
+    test_short_tuple<(u8, u8, u8)> {
+        &[
+            Token::Tuple { len: 1 },
+            Token::U8(1),
+            Token::TupleEnd,
+        ],
+        "invalid length 1, expected a tuple of size 3",
+    }
+    test_short_array<[u8; 3]> {
+        &[
+            Token::Seq { len: Some(1) },
+            Token::U8(1),
+            Token::SeqEnd,
+        ],
+        "invalid length 1, expected an array of length 3",
+    }
+    test_cstring_internal_null<CString> {
+        &[
+            Token::Bytes(b"a\0c"),
+        ],
+        "nul byte found in provided data at position: 1",
+    }
+    test_cstring_internal_null_end<CString> {
+        &[
+            Token::Bytes(b"ac\0"),
+        ],
+        "nul byte found in provided data at position: 2",
+    }
+    test_unit_from_empty_seq<()> {
+        &[
+            Token::Seq { len: Some(0) },
+            Token::SeqEnd,
+        ],
+        "invalid type: sequence, expected unit",
+    }
+    test_unit_from_empty_seq_without_len<()> {
+        &[
+            Token::Seq { len: None },
+            Token::SeqEnd,
+        ],
+        "invalid type: sequence, expected unit",
+    }
+    test_unit_from_tuple_struct<()> {
+        &[
+            Token::TupleStruct { name: "Anything", len: 0 },
+            Token::TupleStructEnd,
+        ],
+        "invalid type: sequence, expected unit",
+    }
+    test_string_from_unit<String> {
+        &[
+            Token::Unit,
+        ],
+        "invalid type: unit value, expected a string",
+    }
+    test_btreeset_from_unit<BTreeSet<isize>> {
+        &[
+            Token::Unit,
+        ],
+        "invalid type: unit value, expected a sequence",
+    }
+    test_btreeset_from_unit_struct<BTreeSet<isize>> {
+        &[
+            Token::UnitStruct { name: "Anything" },
+        ],
+        "invalid type: unit value, expected a sequence",
+    }
+    test_hashset_from_unit<HashSet<isize>> {
+        &[
+            Token::Unit,
+        ],
+        "invalid type: unit value, expected a sequence",
+    }
+    test_hashset_from_unit_struct<HashSet<isize>> {
+        &[
+            Token::UnitStruct { name: "Anything" },
+        ],
+        "invalid type: unit value, expected a sequence",
+    }
+    test_vec_from_unit<Vec<isize>> {
+        &[
+            Token::Unit,
+        ],
+        "invalid type: unit value, expected a sequence",
+    }
+    test_vec_from_unit_struct<Vec<isize>> {
+        &[
+            Token::UnitStruct { name: "Anything" },
+        ],
+        "invalid type: unit value, expected a sequence",
+    }
+    test_zero_array_from_unit<[isize; 0]> {
+        &[
+            Token::Unit,
+        ],
+        "invalid type: unit value, expected an empty array",
+    }
+    test_zero_array_from_unit_struct<[isize; 0]> {
+        &[
+            Token::UnitStruct { name: "Anything" },
+        ],
+        "invalid type: unit value, expected an empty array",
+    }
+    test_btreemap_from_unit<BTreeMap<isize, isize>> {
+        &[
+            Token::Unit,
+        ],
+        "invalid type: unit value, expected a map",
+    }
+    test_btreemap_from_unit_struct<BTreeMap<isize, isize>> {
+        &[
+            Token::UnitStruct { name: "Anything" },
+        ],
+        "invalid type: unit value, expected a map",
+    }
+    test_hashmap_from_unit<HashMap<isize, isize>> {
+        &[
+            Token::Unit,
+        ],
+        "invalid type: unit value, expected a map",
+    }
+    test_hashmap_from_unit_struct<HashMap<isize, isize>> {
+        &[
+            Token::UnitStruct { name: "Anything" },
+        ],
+        "invalid type: unit value, expected a map",
+    }
+    test_bool_from_string<bool> {
+        &[
+            Token::Str("false"),
+        ],
+        "invalid type: string \"false\", expected a boolean",
+    }
+    test_number_from_string<isize> {
+        &[
+            Token::Str("1"),
+        ],
+        "invalid type: string \"1\", expected isize",
+    }
+    test_integer_from_float<isize> {
+        &[
+            Token::F32(0.0),
+        ],
+        "invalid type: floating point `0`, expected isize",
+    }
+    test_unit_struct_from_seq<UnitStruct> {
+        &[
+            Token::Seq { len: Some(0) },
+            Token::SeqEnd,
+        ],
+        "invalid type: sequence, expected unit struct UnitStruct",
+    }
+    test_wrapping_overflow<Wrapping<u16>> {
+        &[
+            Token::U32(65_536),
+        ],
+        "invalid value: integer `65536`, expected u16",
+    }
+    test_duration_overflow_seq<Duration> {
+        &[
+            Token::Seq { len: Some(2) },
+                Token::U64(u64::max_value()),
+                Token::U32(1_000_000_000),
+            Token::SeqEnd,
+        ],
+        "overflow deserializing Duration",
+    }
+    test_duration_overflow_struct<Duration> {
+        &[
+            Token::Struct { name: "Duration", len: 2 },
+                Token::Str("secs"),
+                Token::U64(u64::max_value()),
+
+                Token::Str("nanos"),
+                Token::U32(1_000_000_000),
+            Token::StructEnd,
+        ],
+        "overflow deserializing Duration",
+    }
+    test_systemtime_overflow_seq<SystemTime> {
+        &[
+            Token::Seq { len: Some(2) },
+                Token::U64(u64::max_value()),
+                Token::U32(1_000_000_000),
+            Token::SeqEnd,
+        ],
+        "overflow deserializing SystemTime epoch offset",
+    }
+    test_systemtime_overflow_struct<SystemTime> {
+        &[
+            Token::Struct { name: "SystemTime", len: 2 },
+                Token::Str("secs_since_epoch"),
+                Token::U64(u64::max_value()),
+
+                Token::Str("nanos_since_epoch"),
+                Token::U32(1_000_000_000),
+            Token::StructEnd,
+        ],
+        "overflow deserializing SystemTime epoch offset",
+    }
+    #[cfg(systemtime_checked_add)]
+    test_systemtime_overflow<SystemTime> {
+        &[
+            Token::Seq { len: Some(2) },
+                Token::U64(u64::max_value()),
+                Token::U32(0),
+            Token::SeqEnd,
+        ],
+        "overflow deserializing SystemTime",
+    }
+}
+
+#[test]
+fn test_cstr_internal_null() {
+    assert_de_tokens_error::<Box<CStr>>(
+        &[Token::Bytes(b"a\0c")],
+        "nul byte found in provided data at position: 1",
+    );
+}
+
+#[test]
+fn test_cstr_internal_null_end() {
+    assert_de_tokens_error::<Box<CStr>>(
+        &[Token::Bytes(b"ac\0")],
+        "nul byte found in provided data at position: 2",
+    );
+}
+
+#[cfg(feature = "unstable")]
+#[test]
+fn test_never_type() {
+    assert_de_tokens_error::<!>(&[], "cannot deserialize `!`");
+
+    assert_de_tokens_error::<Result<u8, !>>(
+        &[Token::NewtypeVariant {
+            name: "Result",
+            variant: "Err",
+        }],
+        "cannot deserialize `!`",
+    );
+}