diff --git a/makefile b/makefile
index c239090..85398f7 100644
--- a/makefile
+++ b/makefile
@@ -24,7 +24,7 @@ repl: source
 	$(MAKE) -C repl -k
 
 .PHONY: tests
-tests:
+tests: clean
 	$(MAKE) -C tests -k
 
 #util targets
diff --git a/source/toy_string.c b/source/toy_string.c
index 2fbe958..36ac200 100644
--- a/source/toy_string.c
+++ b/source/toy_string.c
@@ -44,15 +44,21 @@ Toy_String* Toy_toStringLength(Toy_Bucket** bucketHandle, const char* cstring, u
 
 Toy_String* Toy_createStringLength(Toy_Bucket** bucketHandle, const char* cstring, unsigned int length) {
 	Toy_String* ret = (Toy_String*)Toy_partitionBucket(bucketHandle, sizeof(Toy_String));
-	char* data = (char*)Toy_partitionBucket(bucketHandle, length + 1);
 
-	strncpy(data, cstring, length);
+	if (length > 0) { //BUGFIX
+		ret->leaf.data = (char*)Toy_partitionBucket(bucketHandle, length + 1);
+		strncpy((char*)(ret->leaf.data), cstring, length);
+		((char*)(ret->leaf.data))[length] = '\0'; //don't forget the null
+		ret->info.length = length;
+	}
+	else {
+		ret->leaf.data = "";
+		ret->info.length = length;
+	}
 
 	ret->info.type = TOY_STRING_LEAF;
-	ret->info.length = length;
 	ret->info.refCount = 1;
 	ret->info.cachedHash = 0; //don't calc until needed
-	ret->leaf.data = data; //DO make a copy, stored in the bucket
 
 	return ret;
 }
diff --git a/tests/units/test_string.c b/tests/units/test_string.c
index 5250dc4..710959c 100644
--- a/tests/units/test_string.c
+++ b/tests/units/test_string.c
@@ -1,9 +1,775 @@
 #include "toy_string.h"
 #include "toy_console_colors.h"
 
+#include "toy_bucket.h"
+
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int test_sizeof_string_64bit(void) {
+	//test for the correct size
+	{
+		if (sizeof(Toy_String) != 32) {
+			fprintf(stderr, TOY_CC_ERROR "ERROR: 'Toy_String' is an unexpected size in memory: expected 32, found %d \n" TOY_CC_RESET, (int)sizeof(Toy_String));
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+int test_sizeof_string_32bit(void) {
+	//test for the correct size
+	{
+		if (sizeof(Toy_String) != 24) {
+			fprintf(stderr, TOY_CC_ERROR "ERROR: 'Toy_String' is an unexpected size in memory: expected 24, found %d \n" TOY_CC_RESET, (int)sizeof(Toy_String));
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+int test_string_allocation(void) {
+	//allocate a string within a bucket
+	{
+		//setup
+		Toy_Bucket* bucket = Toy_allocateBucket(1024);
+
+		const char* cstring = "Hello world";
+		Toy_String* str = Toy_createStringLength(&bucket, cstring, strlen(cstring));
+
+		//check
+		if (str->info.type != TOY_STRING_LEAF ||
+			str->info.length != 11 ||
+			str->info.refCount != 1 ||
+			strcmp(str->leaf.data, "Hello world") != 0)
+		{
+			fprintf(stderr, TOY_CC_ERROR "ERROR: 'Toy_createStringLength' failed\n" TOY_CC_RESET);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//free the string
+		Toy_freeString(str);
+
+		//inspect the bucket
+		if (bucket->capacity != 1024 ||
+			bucket->count != sizeof(Toy_String) + 12 ||
+			bucket->next != NULL)
+		{
+			fprintf(stderr, TOY_CC_ERROR "ERROR: Unexpected bucket state after 'Toy_createStringLength'\n" TOY_CC_RESET);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//inspect the (now freed) string's memory
+		if (Toy_getStringRefCount(str) != 0) {
+			fprintf(stderr, TOY_CC_ERROR "ERROR: Unexpected string state after it was freed\n" TOY_CC_RESET);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		Toy_freeBucket(&bucket);
+	}
+
+	//copy a string
+	{
+		//setup
+		Toy_Bucket* bucket = Toy_allocateBucket(1024);
+
+		const char* cstring = "Hello world";
+		Toy_String* str = Toy_createStringLength(&bucket, cstring, strlen(cstring));
+
+		//shallow and deep
+		Toy_String* copy = Toy_copyString(str);
+
+		if (str != copy ||
+			str->info.refCount != 2)
+		{
+			fprintf(stderr, TOY_CC_ERROR "ERROR: Failed to copy a string\n" TOY_CC_RESET);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		Toy_freeBucket(&bucket);
+	}
+
+	//allocate a zero-length string
+	{
+		//setup
+		Toy_Bucket* bucket = Toy_allocateBucket(1024);
+
+		const char* cstring = "";
+		Toy_String* str = Toy_createStringLength(&bucket, cstring, 0);
+
+		//check
+		if (str->info.type != TOY_STRING_LEAF ||
+			str->info.length != 0 ||
+			str->info.refCount != 1 ||
+			strcmp(str->leaf.data, "") != 0)
+		{
+			fprintf(stderr, TOY_CC_ERROR "ERROR: Failed to allocate a Toy_String with zero length\n" TOY_CC_RESET);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//free the string
+		Toy_freeString(str);
+
+		Toy_freeBucket(&bucket);
+	}
+
+	return 0;
+}
+
+int test_string_concatenation(void) {
+	//concatenate two strings, and check the refcounts
+	{
+		//setup
+		Toy_Bucket* bucket = Toy_allocateBucket(1024);
+
+		Toy_String* first = Toy_createStringLength(&bucket, "Hello ", 6);
+		Toy_String* second = Toy_createStringLength(&bucket, "world", 5);
+
+		//concatenate
+		Toy_String* result = Toy_concatStrings(&bucket, first, second);
+
+		//check the refcounts
+		if (first->info.refCount != 2 ||
+			second->info.refCount != 2 ||
+			result->info.refCount != 1 ||
+			result->info.length != 11)
+		{
+			fprintf(stderr, TOY_CC_ERROR "ERROR: Unexpected string states after concatenation\n" TOY_CC_RESET);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//clean up the separate strings
+		Toy_freeString(first);
+		Toy_freeString(second);
+
+		//check the refcounts again
+		if (first->info.refCount != 1 ||
+			second->info.refCount != 1 ||
+			result->info.refCount != 1 ||
+			result->info.length != 11)
+		{
+			fprintf(stderr, TOY_CC_ERROR "ERROR: Unexpected string states after concatenation and free\n" TOY_CC_RESET);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//clean up
+		Toy_freeString(result);
+		Toy_freeBucket(&bucket);
+	}
+
+	//concatenate two strings, and check the resulting buffer
+	{
+		//setup
+		Toy_Bucket* bucket = Toy_allocateBucket(1024);
+
+		Toy_String* first = Toy_createStringLength(&bucket, "Hello ", 6);
+		Toy_String* second = Toy_createStringLength(&bucket, "world", 5);
+
+		//concatenate
+		Toy_String* result = Toy_concatStrings(&bucket, first, second);
+
+		char* buffer = Toy_getStringRaw(result);
+
+		//check the refcounts
+		if (strlen(buffer) != 11 ||
+			strncmp(buffer, "Hello world", 11) != 0)
+		{
+			fprintf(stderr, TOY_CC_ERROR "ERROR: Unexpected value of a concatenated string\n" TOY_CC_RESET);
+			free(buffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		free(buffer);
+		Toy_freeString(result);
+		Toy_freeString(first);
+		Toy_freeString(second);
+		Toy_freeBucket(&bucket);
+	}
+
+	return 0;
+}
+
+int test_string_with_stressed_bucket(void) {
+	//how much is that dog in the window?
+	{
+		//test data: 36 characters total, 44 with spaces
+		char* testData[] = {
+			"the",
+			"quick",
+			"brown",
+			"fox",
+			"jumped", //longest word: 6 characters
+			"over",
+			"the",
+			"lazy",
+			"dog", //9 entries long
+			NULL,
+		};
+
+		//setup
+		Toy_Bucket* bucket = Toy_allocateBucket(128);//deliberately too much data for one bucket
+
+		//stress
+		Toy_String* str = Toy_createStringLength(&bucket, testData[0], strlen(testData[0]));
+		Toy_String* ptr = str;
+		for (int i = 1; testData[i]; i++) {
+			str = Toy_concatStrings(&bucket, str, Toy_createStringLength(&bucket, testData[i], strlen(testData[i])));
+		}
+
+		//check
+		if (ptr->info.refCount != 9 ||
+			str->info.length != 36)
+		{
+			fprintf(stderr, TOY_CC_ERROR "ERROR: Unexpected state of the string after stress test\n" TOY_CC_RESET);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//grab the buffer
+		char* buffer = Toy_getStringRaw(str);
+
+		if (strncmp(buffer, "thequickbrownfoxjumpedoverthelazydog", 36) != 0 ||
+			strlen(buffer) != 36)
+		{
+			fprintf(stderr, TOY_CC_ERROR "ERROR: Unexpected state of the string value after stress test: '%s'\n" TOY_CC_RESET, buffer);
+			free(buffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		if (bucket->next == NULL) //just to make sure
+		{
+			fprintf(stderr, TOY_CC_ERROR "ERROR: Unexpected state of the string bucket after stress test\n" TOY_CC_RESET);
+			free(buffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//clean up
+		free(buffer);
+		Toy_freeBucket(&bucket);
+	}
+
+	//
+	return 0;
+}
+
+int test_string_equality(void) {
+	//simple string equality (no concats)
+	{
+		//setup
+		Toy_Bucket* bucket = Toy_allocateBucket(1024);
+		Toy_String* helloWorldOne = Toy_createStringLength(&bucket, "Hello world", 11);
+		Toy_String* helloWorldTwo = Toy_createStringLength(&bucket, "Hello world", 11);
+		Toy_String* helloEveryone = Toy_createStringLength(&bucket, "Hello everyone", 14);
+
+		int result = 0; //for print the errors
+
+		//check match
+		if ((result = Toy_compareStrings(helloWorldOne, helloWorldTwo)) != 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloWorldTwo);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String equality '%s' == '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//check mismatch
+		if ((result = Toy_compareStrings(helloWorldOne, helloEveryone)) == 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloEveryone);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String equality '%s' != '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//check match (same object)
+		if ((result = Toy_compareStrings(helloWorldOne, helloWorldOne)) != 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloWorldOne);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String equality '%s' == '%s' is incorrect, found %s (these are the same object)\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//cleanup
+		Toy_freeBucket(&bucket);
+	}
+
+	//string equality (with concat left)
+	{
+		//setup
+		Toy_Bucket* bucket = Toy_allocateBucket(1024);
+		Toy_String* helloWorldOne = Toy_concatStrings(&bucket, Toy_createStringLength(&bucket, "Hello ", 6), Toy_createStringLength(&bucket, "world", 5));
+		Toy_String* helloWorldTwo = Toy_createStringLength(&bucket, "Hello world", 11);
+		Toy_String* helloEveryone = Toy_createStringLength(&bucket, "Hello everyone", 14);
+
+		int result = 0; //for print the errors
+
+		//check match
+		if ((result = Toy_compareStrings(helloWorldOne, helloWorldTwo)) != 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloWorldTwo);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String concat left equality '%s' == '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//check mismatch
+		if ((result = Toy_compareStrings(helloWorldOne, helloEveryone)) == 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloEveryone);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String concat left equality '%s' != '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//check match (same object)
+		if ((result = Toy_compareStrings(helloWorldOne, helloWorldOne)) != 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloWorldOne);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String concat left equality '%s' == '%s' is incorrect, found %s (these are the same object)\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//cleanup
+		Toy_freeBucket(&bucket);
+	}
+
+	//string equality (with concat right)
+	{
+		//setup
+		Toy_Bucket* bucket = Toy_allocateBucket(1024);
+		Toy_String* helloWorldOne = Toy_createStringLength(&bucket, "Hello world", 11);
+		Toy_String* helloWorldTwo = Toy_concatStrings(&bucket, Toy_createStringLength(&bucket, "Hello ", 6), Toy_createStringLength(&bucket, "world", 5));
+
+		int result = 0; //for print the errors
+
+		//check match
+		if ((result = Toy_compareStrings(helloWorldOne, helloWorldTwo)) != 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloWorldTwo);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String concat right equality '%s' == '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//cleanup
+		Toy_freeBucket(&bucket);
+	}
+
+	//string equality (with concat both)
+	{
+		//setup - these concat points are deliberately different
+		Toy_Bucket* bucket = Toy_allocateBucket(1024);
+		Toy_String* helloWorldOne = Toy_concatStrings(&bucket, Toy_createStringLength(&bucket, "Hello ", 6), Toy_createStringLength(&bucket, "world", 5));
+		Toy_String* helloWorldTwo = Toy_concatStrings(&bucket, Toy_createStringLength(&bucket, "Hello", 5), Toy_createStringLength(&bucket, " world", 6));
+		Toy_String* helloEveryone = Toy_concatStrings(&bucket, Toy_createStringLength(&bucket, "Hell", 4), Toy_createStringLength(&bucket, "world", 5));
+
+		int result = 0; //for print the errors
+
+		//check match
+		if ((result = Toy_compareStrings(helloWorldOne, helloWorldTwo)) != 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloWorldTwo);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String concat both equality '%s' == '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//check mismatch
+		if ((result = Toy_compareStrings(helloWorldOne, helloEveryone)) == 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloEveryone);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String concat both equality '%s' != '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//cleanup
+		Toy_freeBucket(&bucket);
+	}
+
+	//string equality (with concat arbitrary)
+	{
+		//setup - The quick brown fox jumps over the lazy dog.
+		Toy_Bucket* bucket = Toy_allocateBucket(1024);
+		Toy_String* helloWorldOne = Toy_concatStrings(&bucket,
+			Toy_createStringLength(&bucket, "The quick brown ", 16),
+			Toy_concatStrings(&bucket,
+				Toy_createStringLength(&bucket, "fox jumps o", 11),
+				Toy_createStringLength(&bucket, "ver the lazy dog.", 17)
+			)
+		);
+
+		Toy_String* helloWorldTwo = Toy_concatStrings(&bucket,
+			Toy_concatStrings(&bucket,
+				Toy_createStringLength(&bucket, "The quick brown fox", 19),
+				Toy_concatStrings(&bucket,
+					Toy_createStringLength(&bucket, " jumps ove", 10),
+					Toy_createStringLength(&bucket, "r th", 4)
+				)
+			),
+			Toy_concatStrings(&bucket,
+				Toy_createStringLength(&bucket, "e lazy dog", 10),
+				Toy_createStringLength(&bucket, ".", 1)
+			)
+		);
+
+		Toy_String* helloEveryone = Toy_concatStrings(&bucket,
+			Toy_createStringLength(&bucket, "The quick brown fox jumps over ", 31),
+			Toy_concatStrings(&bucket,
+				Toy_createStringLength(&bucket, "the lazy ", 9),
+				Toy_createStringLength(&bucket, "reddit mod.", 11)
+			)
+		);
+
+		int result = 0; //for print the errors
+
+		//check match
+		if ((result = Toy_compareStrings(helloWorldOne, helloWorldTwo)) != 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloWorldTwo);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String concat arbitrary equality '%s' == '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//check mismatch
+		if ((result = Toy_compareStrings(helloWorldOne, helloEveryone)) == 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloEveryone);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String concat arbitrary equality '%s' != '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//cleanup
+		Toy_freeBucket(&bucket);
+	}
+
+	//string equality (empty strings, no concats)
+	{
+		//setup
+		Toy_Bucket* bucket = Toy_allocateBucket(1024);
+		Toy_String* helloWorldOne = Toy_createStringLength(&bucket, "", 0);
+		Toy_String* helloWorldTwo = Toy_createStringLength(&bucket, "", 0);
+		Toy_String* helloEveryone = Toy_createStringLength(&bucket, "Hello everyone", 14);
+
+		int result = 0; //for print the errors
+
+		//check match
+		if ((result = Toy_compareStrings(helloWorldOne, helloWorldTwo)) != 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloWorldTwo);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String equality empty '%s' == '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//check mismatch
+		if ((result = Toy_compareStrings(helloWorldOne, helloEveryone)) == 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloEveryone);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String equality empty '%s' != '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//check mismatch (same object)
+		if ((result = Toy_compareStrings(helloWorldOne, helloWorldOne)) != 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloWorldOne);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String equality empty '%s' == '%s' is incorrect, found %s (these are the same object)\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//cleanup
+		Toy_freeBucket(&bucket);
+	}
+
+	//string equality (empty strings, deep concats)
+	{
+		//setup
+		Toy_Bucket* bucket = Toy_allocateBucket(1024);
+		Toy_String* helloWorldOne = Toy_concatStrings(&bucket,
+			Toy_createStringLength(&bucket, "", 0),
+			Toy_concatStrings(&bucket,
+				Toy_createStringLength(&bucket, "", 0),
+				Toy_createStringLength(&bucket, "", 0)
+			)
+		);
+
+		Toy_String* helloWorldTwo = Toy_concatStrings(&bucket,
+			Toy_concatStrings(&bucket,
+				Toy_createStringLength(&bucket, "", 0),
+				Toy_concatStrings(&bucket,
+					Toy_createStringLength(&bucket, "", 0),
+					Toy_createStringLength(&bucket, "", 0)
+				)
+			),
+			Toy_concatStrings(&bucket,
+				Toy_createStringLength(&bucket, "", 0),
+				Toy_createStringLength(&bucket, "", 0)
+			)
+		);
+
+		Toy_String* helloEveryone = Toy_concatStrings(&bucket,
+			Toy_createStringLength(&bucket, "The quick brown fox jumps over ", 31),
+			Toy_concatStrings(&bucket,
+				Toy_createStringLength(&bucket, "the lazy ", 9),
+				Toy_createStringLength(&bucket, "reddit mod.", 11)
+			)
+		);
+
+		int result = 0; //for print the errors
+
+		//check match
+		if ((result = Toy_compareStrings(helloWorldOne, helloWorldTwo)) != 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloWorldTwo);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String equality empty with concats '%s' == '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//check mismatch
+		if ((result = Toy_compareStrings(helloWorldOne, helloEveryone)) == 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloEveryone);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String equality empty with concats '%s' != '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//check match (same object)
+		if ((result = Toy_compareStrings(helloWorldOne, helloWorldOne)) != 0)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloWorldOne);
+			char* rightBuffer = Toy_getStringRaw(helloWorldOne);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String equality empty with concats '%s' == '%s' is incorrect, found %s (these are the same object)\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//cleanup
+		Toy_freeBucket(&bucket);
+	}
+
+	return 0;
+}
+
+int test_string_diffs(void) {
+	//simple string diffs (no concats)
+	{
+		//setup
+		Toy_Bucket* bucket = Toy_allocateBucket(1024);
+		Toy_String* helloEveryone = Toy_createStringLength(&bucket, "Hello everyone", 14);
+		Toy_String* helloUniverse = Toy_createStringLength(&bucket, "Hello universe", 14);
+
+		int result = 0; //for print the errors
+
+		//check diff
+		if (((result = Toy_compareStrings(helloEveryone, helloUniverse)) < 0) == false)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloEveryone);
+			char* rightBuffer = Toy_getStringRaw(helloUniverse);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String diff '%s' == '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//check diff (reversed)
+		if (((result = Toy_compareStrings(helloUniverse, helloEveryone)) > 0) == false)
+		{
+			char* leftBuffer = Toy_getStringRaw(helloUniverse);
+			char* rightBuffer = Toy_getStringRaw(helloEveryone);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String diff '%s' == '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//cleanup
+		Toy_freeBucket(&bucket);
+	}
+
+	//string diffs (with concat arbitrary)
+	{
+		//setup - The quick brown fox jumps over the lazy dog.
+		Toy_Bucket* bucket = Toy_allocateBucket(1024);
+		Toy_String* pangram = Toy_concatStrings(&bucket,
+			Toy_createStringLength(&bucket, "The quick brown ", 16),
+			Toy_concatStrings(&bucket,
+				Toy_createStringLength(&bucket, "fox jumps o", 11),
+				Toy_createStringLength(&bucket, "ver the lazy dog.", 17)
+			)
+		);
+
+		Toy_String* neckbeard = Toy_concatStrings(&bucket,
+			Toy_createStringLength(&bucket, "The quick brown fox jumps over ", 31),
+			Toy_concatStrings(&bucket,
+				Toy_createStringLength(&bucket, "the lazy ", 9),
+				Toy_createStringLength(&bucket, "reddit mod.", 11)
+			)
+		);
+
+		int result = 0; //for print the errors
+
+		//check diff
+		if (((result = Toy_compareStrings(pangram, neckbeard)) < 0) == false)
+		{
+			char* leftBuffer = Toy_getStringRaw(pangram);
+			char* rightBuffer = Toy_getStringRaw(neckbeard);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String diff '%s' == '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//check diff (reversed)
+		if (((result = Toy_compareStrings(neckbeard, pangram)) > 0) == false)
+		{
+			char* leftBuffer = Toy_getStringRaw(neckbeard);
+			char* rightBuffer = Toy_getStringRaw(pangram);
+			fprintf(stderr, TOY_CC_ERROR "ERROR: String diff '%s' == '%s' is incorrect, found %s\n" TOY_CC_RESET, leftBuffer, rightBuffer, result < 0 ? "<" : result == 0 ? "==" : ">");
+			free(leftBuffer);
+			free(rightBuffer);
+			Toy_freeBucket(&bucket);
+			return -1;
+		}
+
+		//cleanup
+		Toy_freeBucket(&bucket);
+	}
+
+	return 0;
+}
 
 int main(void) {
-	printf(TOY_CC_WARN "Test not yet implemented: %s\n" TOY_CC_RESET, __FILE__);
-	return -1;
-}
+	//run each test set, returning the total errors given
+	int total = 0, res = 0;
+
+	{
+#if TOY_BITNESS == 64
+		res = test_sizeof_string_64bit();
+#else
+		res = test_sizeof_string_32bit();
+#endif
+		if (res == 0) {
+			printf(TOY_CC_NOTICE "All good\n" TOY_CC_RESET);
+		}
+		total += res;
+	}
+
+	{
+		res = test_string_allocation();
+		if (res == 0) {
+			printf(TOY_CC_NOTICE "All good\n" TOY_CC_RESET);
+		}
+		total += res;
+	}
+
+	{
+		res = test_string_concatenation();
+		if (res == 0) {
+			printf(TOY_CC_NOTICE "All good\n" TOY_CC_RESET);
+		}
+		total += res;
+	}
+
+	{
+		res = test_string_with_stressed_bucket();
+		if (res == 0) {
+			printf(TOY_CC_NOTICE "All good\n" TOY_CC_RESET);
+		}
+		total += res;
+	}
+
+	{
+		res = test_string_equality();
+		if (res == 0) {
+			printf(TOY_CC_NOTICE "All good\n" TOY_CC_RESET);
+		}
+		total += res;
+	}
+
+	{
+		res = test_string_diffs();
+		if (res == 0) {
+			printf(TOY_CC_NOTICE "All good\n" TOY_CC_RESET);
+		}
+		total += res;
+	}
+
+	//NOTE: string fragmentation is no longer supported
+
+	return total;
+}
\ No newline at end of file