diff --git a/lib/std/hash/adler.zig b/lib/std/hash/adler.zig
index 200dc9aafe..52f7b2691a 100644
--- a/lib/std/hash/adler.zig
+++ b/lib/std/hash/adler.zig
@@ -3,7 +3,7 @@
 // https://tools.ietf.org/html/rfc1950#section-9
 // https://github.com/madler/zlib/blob/master/adler32.c
 
-const std = @import("../std.zig");
+const std = @import("std");
 const testing = std.testing;
 
 pub const Adler32 = struct {
@@ -126,3 +126,9 @@ test "adler32 very long with variation" {
 
     try testing.expectEqual(@as(u32, 0x5af38d6e), std.hash.Adler32.hash(long[0..]));
 }
+
+const verify = @import("verify.zig");
+
+test "adler32 iterative" {
+    try verify.iterativeApi(Adler32);
+}
diff --git a/lib/std/hash/cityhash.zig b/lib/std/hash/cityhash.zig
index 8040c99b84..2fab089095 100644
--- a/lib/std/hash/cityhash.zig
+++ b/lib/std/hash/cityhash.zig
@@ -342,64 +342,35 @@ pub const CityHash64 = struct {
     }
 };
 
-fn SMHasherTest(comptime hash_fn: anytype) u32 {
-    const HashResult = @typeInfo(@TypeOf(hash_fn)).Fn.return_type.?;
-
-    var key: [256]u8 = undefined;
-    var hashes_bytes: [256 * @sizeOf(HashResult)]u8 = undefined;
-
-    @memset(&key, 0);
-    @memset(&hashes_bytes, 0);
-
-    var i: u32 = 0;
-    while (i < 256) : (i += 1) {
-        key[i] = @as(u8, @intCast(i));
-
-        var h: HashResult = hash_fn(key[0..i], 256 - i);
-
-        // comptime can't really do reinterpret casting yet,
-        // so we need to write the bytes manually.
-        for (hashes_bytes[i * @sizeOf(HashResult) ..][0..@sizeOf(HashResult)]) |*byte| {
-            byte.* = @as(u8, @truncate(h));
-            h = h >> 8;
-        }
-    }
-
-    return @as(u32, @truncate(hash_fn(&hashes_bytes, 0)));
-}
-
 fn CityHash32hashIgnoreSeed(str: []const u8, seed: u32) u32 {
     _ = seed;
     return CityHash32.hash(str);
 }
 
+const verify = @import("verify.zig");
+
 test "cityhash32" {
     const Test = struct {
-        fn doTest() !void {
-            // Note: SMHasher doesn't provide a 32bit version of the algorithm.
-            // Note: The implementation was verified against the Google Abseil version.
-            try std.testing.expectEqual(SMHasherTest(CityHash32hashIgnoreSeed), 0x68254F81);
-            try std.testing.expectEqual(SMHasherTest(CityHash32hashIgnoreSeed), 0x68254F81);
+        fn do() !void {
+            // SMHasher doesn't provide a 32bit version of the algorithm.
+            // The implementation was verified against the Google Abseil version.
+            try std.testing.expectEqual(verify.smhasher(CityHash32hashIgnoreSeed), 0x68254F81);
         }
     };
-    try Test.doTest();
-    // TODO This is uncommented to prevent OOM on the CI server. Re-enable this test
-    // case once we ship stage2.
-    //@setEvalBranchQuota(50000);
-    //comptime Test.doTest();
+    try Test.do();
+    @setEvalBranchQuota(75000);
+    try comptime Test.do();
 }
 
 test "cityhash64" {
     const Test = struct {
-        fn doTest() !void {
-            // Note: This is not compliant with the SMHasher implementation of CityHash64!
-            // Note: The implementation was verified against the Google Abseil version.
-            try std.testing.expectEqual(SMHasherTest(CityHash64.hashWithSeed), 0x5FABC5C5);
+        fn do() !void {
+            // This is not compliant with the SMHasher implementation of CityHash64!
+            // The implementation was verified against the Google Abseil version.
+            try std.testing.expectEqual(verify.smhasher(CityHash64.hashWithSeed), 0x5FABC5C5);
         }
     };
-    try Test.doTest();
-    // TODO This is uncommented to prevent OOM on the CI server. Re-enable this test
-    // case once we ship stage2.
-    //@setEvalBranchQuota(50000);
-    //comptime Test.doTest();
+    try Test.do();
+    @setEvalBranchQuota(75000);
+    try comptime Test.do();
 }
diff --git a/lib/std/hash/crc.zig b/lib/std/hash/crc.zig
index 9a5936874d..cbd3c75d4d 100644
--- a/lib/std/hash/crc.zig
+++ b/lib/std/hash/crc.zig
@@ -5,7 +5,7 @@
 // - Crc32SmallWithPoly uses only 64 bytes of memory but is slower. Be aware that this is
 //   still moderately fast just slow relative to the slicing approach.
 
-const std = @import("../std.zig");
+const std = @import("std");
 const builtin = @import("builtin");
 const debug = std.debug;
 const testing = std.testing;
@@ -194,6 +194,8 @@ pub fn Crc32WithPoly(comptime poly: Polynomial) type {
     };
 }
 
+const verify = @import("verify.zig");
+
 test "crc32 ieee" {
     const Crc32Ieee = Crc32WithPoly(.IEEE);
 
@@ -210,6 +212,10 @@ test "crc32 castagnoli" {
     try testing.expect(Crc32Castagnoli.hash("abc") == 0x364b3fb7);
 }
 
+test "crc32 iterative" {
+    try verify.iterativeApi(Crc32WithPoly(.IEEE));
+}
+
 // half-byte lookup table implementation.
 pub fn Crc32SmallWithPoly(comptime poly: Polynomial) type {
     return struct {
@@ -258,6 +264,10 @@ pub fn Crc32SmallWithPoly(comptime poly: Polynomial) type {
     };
 }
 
+test "small crc32 iterative" {
+    try verify.iterativeApi(Crc32SmallWithPoly(.IEEE));
+}
+
 test "small crc32 ieee" {
     const Crc32Ieee = Crc32SmallWithPoly(.IEEE);
 
diff --git a/lib/std/hash/crc/catalog_test.zig b/lib/std/hash/crc/catalog_test.zig
index b9bf21fc99..ab89745ca8 100644
--- a/lib/std/hash/crc/catalog_test.zig
+++ b/lib/std/hash/crc/catalog_test.zig
@@ -1,6 +1,6 @@
 //! This file is auto-generated by tools/update_crc_catalog.zig.
 
-const std = @import("../../std.zig");
+const std = @import("std");
 const testing = std.testing;
 const catalog = @import("catalog.zig");
 
diff --git a/lib/std/hash/fnv.zig b/lib/std/hash/fnv.zig
index 3175f26820..01469bff8a 100644
--- a/lib/std/hash/fnv.zig
+++ b/lib/std/hash/fnv.zig
@@ -4,7 +4,7 @@
 //
 // https://tools.ietf.org/html/draft-eastlake-fnv-14
 
-const std = @import("../std.zig");
+const std = @import("std");
 const testing = std.testing;
 
 pub const Fnv1a_32 = Fnv1a(u32, 0x01000193, 0x811c9dc5);
@@ -40,19 +40,24 @@ fn Fnv1a(comptime T: type, comptime prime: T, comptime offset: T) type {
     };
 }
 
+const verify = @import("verify.zig");
+
 test "fnv1a-32" {
     try testing.expect(Fnv1a_32.hash("") == 0x811c9dc5);
     try testing.expect(Fnv1a_32.hash("a") == 0xe40c292c);
     try testing.expect(Fnv1a_32.hash("foobar") == 0xbf9cf968);
+    try verify.iterativeApi(Fnv1a_32);
 }
 
 test "fnv1a-64" {
     try testing.expect(Fnv1a_64.hash("") == 0xcbf29ce484222325);
     try testing.expect(Fnv1a_64.hash("a") == 0xaf63dc4c8601ec8c);
     try testing.expect(Fnv1a_64.hash("foobar") == 0x85944171f73967e8);
+    try verify.iterativeApi(Fnv1a_64);
 }
 
 test "fnv1a-128" {
     try testing.expect(Fnv1a_128.hash("") == 0x6c62272e07bb014262b821756295c58d);
     try testing.expect(Fnv1a_128.hash("a") == 0xd228cb696f1a8caf78912b704e4a8964);
+    try verify.iterativeApi(Fnv1a_128);
 }
diff --git a/lib/std/hash/murmur.zig b/lib/std/hash/murmur.zig
index f6af810c6e..80496be24f 100644
--- a/lib/std/hash/murmur.zig
+++ b/lib/std/hash/murmur.zig
@@ -279,26 +279,9 @@ pub const Murmur3_32 = struct {
     }
 };
 
-fn SMHasherTest(comptime hash_fn: anytype, comptime hashbits: u32) u32 {
-    const hashbytes = hashbits / 8;
-    var key: [256]u8 = [1]u8{0} ** 256;
-    var hashes: [hashbytes * 256]u8 = [1]u8{0} ** (hashbytes * 256);
-
-    var i: u32 = 0;
-    while (i < 256) : (i += 1) {
-        key[i] = @as(u8, @truncate(i));
-
-        var h = hash_fn(key[0..i], 256 - i);
-        if (native_endian == .Big)
-            h = @byteSwap(h);
-        @memcpy(hashes[i * hashbytes ..][0..hashbytes], @as([*]u8, @ptrCast(&h)));
-    }
-
-    return @as(u32, @truncate(hash_fn(&hashes, 0)));
-}
+const verify = @import("verify.zig");
 
 test "murmur2_32" {
-    try testing.expectEqual(SMHasherTest(Murmur2_32.hashWithSeed, 32), 0x27864C1E);
     var v0: u32 = 0x12345678;
     var v1: u64 = 0x1234567812345678;
     var v0le: u32 = v0;
@@ -311,8 +294,18 @@ test "murmur2_32" {
     try testing.expectEqual(Murmur2_32.hash(@as([*]u8, @ptrCast(&v1le))[0..8]), Murmur2_32.hashUint64(v1));
 }
 
+test "murmur2_32 smhasher" {
+    const Test = struct {
+        fn do() !void {
+            try testing.expectEqual(verify.smhasher(Murmur2_32.hashWithSeed), 0x27864C1E);
+        }
+    };
+    try Test.do();
+    @setEvalBranchQuota(30000);
+    try comptime Test.do();
+}
+
 test "murmur2_64" {
-    try std.testing.expectEqual(SMHasherTest(Murmur2_64.hashWithSeed, 64), 0x1F0D3804);
     var v0: u32 = 0x12345678;
     var v1: u64 = 0x1234567812345678;
     var v0le: u32 = v0;
@@ -325,8 +318,18 @@ test "murmur2_64" {
     try testing.expectEqual(Murmur2_64.hash(@as([*]u8, @ptrCast(&v1le))[0..8]), Murmur2_64.hashUint64(v1));
 }
 
+test "mumur2_64 smhasher" {
+    const Test = struct {
+        fn do() !void {
+            try std.testing.expectEqual(verify.smhasher(Murmur2_64.hashWithSeed), 0x1F0D3804);
+        }
+    };
+    try Test.do();
+    @setEvalBranchQuota(30000);
+    try comptime Test.do();
+}
+
 test "murmur3_32" {
-    try std.testing.expectEqual(SMHasherTest(Murmur3_32.hashWithSeed, 32), 0xB0F57EE3);
     var v0: u32 = 0x12345678;
     var v1: u64 = 0x1234567812345678;
     var v0le: u32 = v0;
@@ -338,3 +341,14 @@ test "murmur3_32" {
     try testing.expectEqual(Murmur3_32.hash(@as([*]u8, @ptrCast(&v0le))[0..4]), Murmur3_32.hashUint32(v0));
     try testing.expectEqual(Murmur3_32.hash(@as([*]u8, @ptrCast(&v1le))[0..8]), Murmur3_32.hashUint64(v1));
 }
+
+test "mumur3_32 smhasher" {
+    const Test = struct {
+        fn do() !void {
+            try std.testing.expectEqual(verify.smhasher(Murmur3_32.hashWithSeed), 0xB0F57EE3);
+        }
+    };
+    try Test.do();
+    @setEvalBranchQuota(30000);
+    try comptime Test.do();
+}
diff --git a/lib/std/hash/verify.zig b/lib/std/hash/verify.zig
new file mode 100644
index 0000000000..1a20d8d1a3
--- /dev/null
+++ b/lib/std/hash/verify.zig
@@ -0,0 +1,62 @@
+const std = @import("std");
+
+fn hashMaybeSeed(comptime hash_fn: anytype, seed: anytype, buf: []const u8) @typeInfo(@TypeOf(hash_fn)).Fn.return_type.? {
+    const HashFn = @typeInfo(@TypeOf(hash_fn)).Fn;
+    if (HashFn.params.len > 1) {
+        if (@typeInfo(HashFn.params[0].type.?) == .Int) {
+            return hash_fn(@intCast(seed), buf);
+        } else {
+            return hash_fn(buf, @intCast(seed));
+        }
+    } else {
+        return hash_fn(buf);
+    }
+}
+
+fn initMaybeSeed(comptime Hash: anytype, seed: anytype) Hash {
+    const HashFn = @typeInfo(@TypeOf(Hash.init)).Fn;
+    if (HashFn.params.len == 1) {
+        return Hash.init(@intCast(seed));
+    } else {
+        return Hash.init();
+    }
+}
+
+// Returns a verification code, the same as used by SMHasher.
+//
+// Hash keys of the form {0}, {0,1}, {0,1,2}... up to N=255, using 256-N as seed.
+// First four-bytes of the hash, interpreted as little-endian is the verification code.
+pub fn smhasher(comptime hash_fn: anytype) u32 {
+    const HashFnTy = @typeInfo(@TypeOf(hash_fn)).Fn;
+    const HashResult = HashFnTy.return_type.?;
+    const hash_size = @sizeOf(HashResult);
+
+    var buf: [256]u8 = undefined;
+    var buf_all: [256 * hash_size]u8 = undefined;
+
+    for (0..256) |i| {
+        buf[i] = @intCast(i);
+        const h = hashMaybeSeed(hash_fn, 256 - i, buf[0..i]);
+        std.mem.writeIntLittle(HashResult, buf_all[i * hash_size ..][0..hash_size], h);
+    }
+
+    return @truncate(hashMaybeSeed(hash_fn, 0, buf_all[0..]));
+}
+
+pub fn iterativeApi(comptime Hash: anytype) !void {
+    // Sum(1..32) = 528
+    var buf: [528]u8 = [_]u8{0} ** 528;
+    var len: usize = 0;
+    const seed = 0;
+
+    var hasher = initMaybeSeed(Hash, seed);
+    for (1..32) |i| {
+        const r = hashMaybeSeed(Hash.hash, seed, buf[0 .. len + i]);
+        hasher.update(buf[len..][0..i]);
+        const f1 = hasher.final();
+        const f2 = hasher.final();
+        if (f1 != f2) return error.IterativeHashWasNotIdempotent;
+        if (f1 != r) return error.IterativeHashDidNotMatchDirect;
+        len += i;
+    }
+}
diff --git a/lib/std/hash/wyhash.zig b/lib/std/hash/wyhash.zig
index acce3a7732..91cdf5007f 100644
--- a/lib/std/hash/wyhash.zig
+++ b/lib/std/hash/wyhash.zig
@@ -66,7 +66,7 @@ pub const Wyhash = struct {
     }
 
     pub fn final(self: *Wyhash) u64 {
-        var input = self.buf[0..self.buf_len];
+        var input: []const u8 = self.buf[0..self.buf_len];
         var newSelf = self.shallowCopy(); // ensure idempotency
 
         if (self.total_len <= 16) {
@@ -196,6 +196,7 @@ pub const Wyhash = struct {
     }
 };
 
+const verify = @import("verify.zig");
 const expectEqual = std.testing.expectEqual;
 
 const TestVector = struct {
@@ -229,51 +230,26 @@ test "test vectors at comptime" {
     }
 }
 
-test "test vectors streaming" {
-    const step = 5;
-
-    for (vectors) |e| {
-        var wh = Wyhash.init(e.seed);
-        var i: usize = 0;
-        while (i < e.input.len) : (i += step) {
-            const len = if (i + step > e.input.len) e.input.len - i else step;
-            wh.update(e.input[i..][0..len]);
+test "smhasher" {
+    const Test = struct {
+        fn do() !void {
+            try expectEqual(verify.smhasher(Wyhash.hash), 0xBD5E840C);
         }
-        try expectEqual(e.expected, wh.final());
-    }
+    };
+    try Test.do();
+    @setEvalBranchQuota(50000);
+    try comptime Test.do();
 }
 
-test "test ensure idempotent final call" {
-    const e: TestVector = .{ .seed = 6, .expected = 0xc39cab13b115aad3, .input = "12345678901234567890123456789012345678901234567890123456789012345678901234567890" };
-    var wh = Wyhash.init(e.seed);
-    wh.update(e.input);
-
-    for (0..10) |_| {
-        try expectEqual(e.expected, wh.final());
-    }
-}
-
-test "iterative non-divisible update" {
-    var buf: [8192]u8 = undefined;
-    for (&buf, 0..) |*e, i| {
-        e.* = @as(u8, @truncate(i));
-    }
-
-    const seed = 0x128dad08f;
-
-    var end: usize = 32;
-    while (end < buf.len) : (end += 32) {
-        const non_iterative_hash = Wyhash.hash(seed, buf[0..end]);
-
-        var wy = Wyhash.init(seed);
-        var i: usize = 0;
-        while (i < end) : (i += 33) {
-            wy.update(buf[i..@min(i + 33, end)]);
+test "iterative api" {
+    const Test = struct {
+        fn do() !void {
+            try verify.iterativeApi(Wyhash);
         }
-        const iterative_hash = wy.final();
-
-        try std.testing.expectEqual(iterative_hash, non_iterative_hash);
-    }
+    };
+    try Test.do();
+    @setEvalBranchQuota(50000);
+    try comptime Test.do();
 }
 
 test "iterative maintains last sixteen" {
diff --git a/lib/std/hash/xxhash.zig b/lib/std/hash/xxhash.zig
index 8e25b9ce7b..1f44183b6c 100644
--- a/lib/std/hash/xxhash.zig
+++ b/lib/std/hash/xxhash.zig
@@ -438,6 +438,8 @@ fn validateType(comptime T: type) void {
     }
 }
 
+const verify = @import("verify.zig");
+
 fn testExpect(comptime H: type, seed: anytype, input: []const u8, expected: u64) !void {
     try expectEqual(expected, H.hash(0, input));
 
@@ -457,6 +459,28 @@ test "xxhash64" {
     try testExpect(H, 0, "12345678901234567890123456789012345678901234567890123456789012345678901234567890", 0xe04a477f19ee145d);
 }
 
+test "xxhash64 smhasher" {
+    const Test = struct {
+        fn do() !void {
+            try expectEqual(verify.smhasher(XxHash64.hash), 0x024B7CF4);
+        }
+    };
+    try Test.do();
+    @setEvalBranchQuota(75000);
+    comptime try Test.do();
+}
+
+test "xxhash64 iterative api" {
+    const Test = struct {
+        fn do() !void {
+            try verify.iterativeApi(XxHash64);
+        }
+    };
+    try Test.do();
+    @setEvalBranchQuota(30000);
+    comptime try Test.do();
+}
+
 test "xxhash32" {
     const H = XxHash32;
 
@@ -468,3 +492,25 @@ test "xxhash32" {
     try testExpect(H, 0, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789", 0x9c285e64);
     try testExpect(H, 0, "12345678901234567890123456789012345678901234567890123456789012345678901234567890", 0x9c05f475);
 }
+
+test "xxhash32 smhasher" {
+    const Test = struct {
+        fn do() !void {
+            try expectEqual(verify.smhasher(XxHash32.hash), 0xBA88B743);
+        }
+    };
+    try Test.do();
+    @setEvalBranchQuota(75000);
+    comptime try Test.do();
+}
+
+test "xxhash32 iterative api" {
+    const Test = struct {
+        fn do() !void {
+            try verify.iterativeApi(XxHash32);
+        }
+    };
+    try Test.do();
+    @setEvalBranchQuota(30000);
+    comptime try Test.do();
+}
diff --git a/tools/update_crc_catalog.zig b/tools/update_crc_catalog.zig
index 81b20b7dfa..0e8d9b3ef8 100644
--- a/tools/update_crc_catalog.zig
+++ b/tools/update_crc_catalog.zig
@@ -55,7 +55,7 @@ pub fn main() anyerror!void {
     try test_writer.writeAll(
         \\//! This file is auto-generated by tools/update_crc_catalog.zig.
         \\
-        \\const std = @import("../../std.zig");
+        \\const std = @import("std");
         \\const testing = std.testing;
         \\const catalog = @import("catalog.zig");
         \\