diff --git a/src/hmapTest.c b/src/hmapTest.c
new file mode 100644
index 0000000..491ec28
--- /dev/null
+++ b/src/hmapTest.c
@@ -0,0 +1,98 @@
+#include "ktest.h"
+#include "hmap.h"
+
+KTEST(hmapSetGetOverwrite)
+{
+    Hmap h;
+    KT_TRUE(t, hmapInit(&h, 8));
+    KT_EQ(t, hmapCount(&h), 0);
+
+    int a = 1, b = 2;
+    KT_TRUE(t, hmapSet(&h, "alpha", &a));
+    KT_TRUE(t, hmapSet(&h, "beta", &b));
+    KT_EQ(t, hmapCount(&h), 2);
+
+    KT_EQP(t, hmapGet(&h, "alpha"), &a);
+    KT_EQP(t, hmapGet(&h, "beta"), &b);
+    KT_NULL(t, hmapGet(&h, "gamma"));
+    KT_TRUE(t, hmapHas(&h, "alpha"));
+    KT_FALSE(t, hmapHas(&h, "gamma"));
+
+    int c = 3;
+    KT_TRUE(t, hmapSet(&h, "alpha", &c));   /* overwrite, not a new entry */
+    KT_EQ(t, hmapCount(&h), 2);
+    KT_EQP(t, hmapGet(&h, "alpha"), &c);
+
+    hmapFree(&h);
+}
+
+KTEST(hmapRemove)
+{
+    Hmap h;
+    hmapInit(&h, 4);
+
+    int v = 42;
+    hmapSet(&h, "key", &v);
+    KT_TRUE(t, hmapRemove(&h, "key"));
+    KT_EQ(t, hmapCount(&h), 0);
+    KT_NULL(t, hmapGet(&h, "key"));
+    KT_FALSE(t, hmapRemove(&h, "key"));   /* already gone */
+
+    hmapFree(&h);
+}
+
+KTEST(hmapCollisionsChain)
+{
+    /* force collisions with a tiny bucket count so every key lands in the
+       same chain, exercising the linked-list walk in findSlot */
+    Hmap h;
+    hmapInit(&h, 1);
+
+    int values[10];
+    char keys[10][8];
+    for (int i = 0; i < 10; i++) {
+        values[i] = i * 10;
+        keys[i][0] = 'k';
+        keys[i][1] = (char)('0' + i);
+        keys[i][2] = 0;
+        KT_TRUE(t, hmapSet(&h, keys[i], &values[i]));
+    }
+    KT_EQ(t, hmapCount(&h), 10);
+
+    for (int i = 0; i < 10; i++)
+        KT_EQP(t, hmapGet(&h, keys[i]), &values[i]);
+
+    hmapFree(&h);
+}
+
+KTEST(hmapHashIsDeterministicAndDistributes)
+{
+    KT_EQU(t, hmapHashString("same"), hmapHashString("same"));
+    KT_NE(t, hmapHashString("alpha"), hmapHashString("beta"));
+    KT_NE(t, hmapHashString(""), hmapHashString("a"));
+}
+
+static bool sumVisitor(const char* key, void* value, void* userData)
+{
+    (void)key;
+    int64* sum = (int64*)userData;
+    *sum += *(int*)value;
+    return true;
+}
+
+KTEST(hmapForEachVisitsAll)
+{
+    Hmap h;
+    hmapInit(&h, 4);
+
+    int a = 1, b = 2, c = 3;
+    hmapSet(&h, "a", &a);
+    hmapSet(&h, "b", &b);
+    hmapSet(&h, "c", &c);
+
+    int64 sum = 0;
+    hmapForEach(&h, sumVisitor, &sum);
+    KT_EQ(t, sum, 6);
+
+    hmapFree(&h);
+}