From 424e1f2a3eb59b97462c5e15ef13b80c66f4ba1b Mon Sep 17 00:00:00 2001
From: Thomas Schmucker <ts@its1.de>
Date: Sun, 10 Apr 2022 10:28:39 +0200
Subject: feat: added tests

---
 src/stack-array.c | 106 +++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 74 insertions(+), 32 deletions(-)

diff --git a/src/stack-array.c b/src/stack-array.c
index 5f4ba41..a36de7b 100644
--- a/src/stack-array.c
+++ b/src/stack-array.c
@@ -1,3 +1,4 @@
+#include <assert.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -23,37 +24,53 @@ stack_init(struct stack *stack)
 }
 /* -->8-- */
 
-/* --8<-- stack2_push */
-bool
-stack_push(struct stack *stack, T data)
+/* --8<-- stack2_grow_if_needed */
+static bool
+stack_grow_if_needed(struct stack *stack)
 {
-	if ( stack->array == NULL ) {
-		if ( (stack->array = malloc(10 * sizeof *stack->array)) != NULL ) {
-			stack->sz = 10;
-			stack->p  = 0;
+	if ( stack->p == stack->sz ) {
+		if ( stack->array == NULL ) {
+			static const size_t initial_size = 10;
+
+			if ( (stack->array = reallocarray(NULL, initial_size, sizeof stack->array[0])) != NULL ) {
+				stack->sz = initial_size;
+				stack->p  = 0;
+			}
+			else {
+				ERROR("out of memory");
+				return false;
+			}
 		}
 		else {
-			ERROR("out of memory");
-			return false;
+			const size_t new_size = stack->sz * 3 / 2;
+
+			T *new_array;
+
+			if ( (new_array = reallocarray(stack->array, new_size, sizeof stack->array[0])) != NULL ) {
+				stack->array = new_array;
+				stack->sz    = new_size;
+			}
+			else {
+				ERROR("out of memory");
+				return false;
+			}
 		}
 	}
+	return true;
+}
+/* -->8-- */
 
-	if ( stack->p == stack->sz ) {
-		size_t new_sz;
-		T *    new_array;
+/* --8<-- stack2_push */
+bool
+stack_push(struct stack *stack, T data)
+{
+	bool success = stack_grow_if_needed(stack);
 
-		if ( (new_array = realloc(stack->array, (new_sz = (stack->sz * 3 / 2)) * sizeof *stack->array)) != NULL ) {
-			stack->array = new_array;
-			stack->sz    = new_sz;
-		}
-		else {
-			ERROR("out of memory");
-			return false;
-		}
+	if ( success ) {
+		stack->array[stack->p++] = data;
 	}
 
-	stack->array[stack->p++] = data;
-	return true;
+	return success;
 }
 /* -->8-- */
 
@@ -90,26 +107,51 @@ stack_free(struct stack *stack)
 }
 /* -->8-- */
 
-int
-main()
+void
+test_stack(void)
 {
 	struct stack stack[1];
 
 	stack_init(stack);
 
-	for ( int i = 0; i != 20; ++i )
+	assert(stack_empty(stack) == true);
+
+	for ( int i = 0; i != 5; ++i )
 		stack_push(stack, i);
 
-	while ( !stack_empty(stack) ) {
-		int i;
+	assert(stack_empty(stack) == false);
 
-		if ( stack_pop(stack, &i) )
-			printf("%d\n", i);
-		else
-			ERROR("this shouldn't happen!");
-	}
+	T i;
+	assert(stack_pop(stack, &i) == true);
+	assert(i == 4);
+	assert(stack_pop(stack, &i) == true);
+	assert(i == 3);
+	assert(stack_pop(stack, &i) == true);
+	assert(i == 2);
+	assert(stack_pop(stack, &i) == true);
+	assert(i == 1);
+	assert(stack_pop(stack, &i) == true);
+	assert(i == 0);
+
+	assert(stack_pop(stack, &i) == false);
+
+	assert(stack_empty(stack) == true);
+
+	assert(stack[0].sz == 10);
+	assert(stack[0].p == 0);
+
+	for ( int i = 0; i != 23; ++i )
+		stack_push(stack, i);
+
+	assert(stack[0].sz == 33);
+	assert(stack[0].p == 23);
 
 	stack_free(stack);
+}
 
+int
+main()
+{
+	test_stack();
 	return EXIT_SUCCESS;
 }
-- 
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