make sure last_log changes, but isn't null on append

test/append-test-log.c

@@ -21,6 +21,7 @@
 
 #include <u.h>
 #include <libc.h>
+#include <stdio.h>
 
 #include "../9unit.h"
 #include "util.h"
@@ -29,6 +30,15 @@
 // Local Prototypes
 
 static void append_to_empty(TestState *);
+static void append_to_existing(TestState *);
+
+static void chk_ptr_chg(
+	TestState *,
+	const char *,
+	const char *,
+	const void *,
+	const void *
+);
 
 // Public Functions
 
@@ -37,6 +47,7 @@ test_append_test_log(TestState *s)
 {
 	print("append_test_log()\n");
 	append_to_empty(s);
+	append_to_existing(s);
 }
 
 // Local Functions
@@ -77,4 +88,76 @@ append_to_empty(TestState *s)
 	);
 }
 
+static void
+append_to_existing(TestState *s)
+{
+	TestState test;
+	TestLogEntry first, second;
+	print("\tappend to existing\n");
+
+	// build initial state/log
+	mk_sample_state(&test);
+	first.text = "foo";
+	first.next = &second;
+	second.text = "bar";
+	second.next = 0;
+	test.first_log = &first;
+	test.last_log = &second;
+
+	append_test_log(&test, "baz");
+
+	// first shouldn't change
+	print("\t\tfirst_log\n");
+	chk_ptr_eq(
+		s,
+		"ERROR: append_test_log(): first_log:",
+		test.first_log,
+		&first
+	);
+
+	// last should change
+	print("\t\tlast_log\n");
+	chk_ptr_chg(
+		s,
+		"\t\t\t",
+		"ERROR: append_test_log(): last_log:",
+		test.last_log,
+		&second
+	);
+}
+
+static void
+chk_ptr_chg(
+	TestState *s,
+	const char *prefix,
+	const char *context,
+	const void *actual,
+	const void *prohibited
+)
+{
+	char str[STR_BUF_SIZE];
+
+	// make sure it's changed
+	print(prefix);
+	print("changed\n");
+	snprintf(str, STR_BUF_SIZE, "%s changed:", context);
+	chk_ptr_ne(
+		s,
+		str,
+		actual,
+		prohibited
+	);
+
+	// make sure it's not null
+	print(prefix);
+	print("not null\n");
+	snprintf(str, STR_BUF_SIZE, "%s not null:", context);
+	chk_ptr_ne(
+		s,
+		str,
+		actual,
+		0
+	);
+}
+
 //jl