diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index ffb7a64..99b839e 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -40,3 +40,8 @@ the agent to update the implementation.
 
 When creating a commit, make sure that both the user's and the agent's modifications
 are included in the commit.
+
+Only create a commit when specifically asked for that. Never assume implicitly that the
+user wants you to create a commit.
+Even if they asked you to create a commit in an earlier task, it does not mean that
+you should also create a commit in a later task.
diff --git a/v0/test.c b/v0/test.c
index ce48420..63a2457 100644
--- a/v0/test.c
+++ b/v0/test.c
@@ -4,6 +4,7 @@
 #include <string.h>
 #include <stdlib.h>
 #include "util.h"
+#include "parser.h"
 
 static jmp_buf s_testJmp;
 static const char* s_failMsg;
@@ -16,22 +17,6 @@ void fail(const char* msg) {
     longjmp(s_testJmp, 1);
 }
 
-void assert_not_null(void* ptr, const char* msg) {
-    if (ptr == NULL) {
-        fail(msg);
-    }
-}
-
-void assert_str(const char* expected, const char* actual, const char* msg) {
-    if (expected == NULL || actual == NULL || strcmp(expected, actual) != 0) {
-        fail(msg);
-    }
-}
-
-void assert_log(const char* expected, const char* msg) {
-    assert_str(expected, s_logOutput, msg);
-}
-
 char* read_file_content(const char* filepath) {
     FILE* f;
     long size;
@@ -53,6 +38,56 @@ char* read_file_content(const char* filepath) {
     return content;
 }
 
+void assert_not_null(void* ptr, const char* msg) {
+    if (ptr == NULL) {
+        fail(msg);
+    }
+}
+
+void assert_string(const char* expected, String actual, const char* msg) {
+    if (expected == NULL || actual.data == NULL || strlen(expected) != actual.length || strncmp(expected, actual.data, actual.length) != 0) {
+        fail(msg);
+    }
+}
+
+void assert_str(const char* expected, const char* actual, const char* msg) {
+    if (expected == NULL || actual == NULL || strcmp(expected, actual) != 0) {
+        fail(msg);
+    }
+}
+
+TokenStream* tokenstream_get_test(void) {
+    char* filepath = NULL;
+    TokenStream* ts = NULL;
+
+    filepath = format_string("v0/tests/%s.c2", s_currentTestName);
+    if (!filepath) {
+        fail("out of memory");
+        return NULL;
+    }
+    
+    if (s_testSource) free(s_testSource);
+    s_testSource = read_file_content(filepath);
+    if (!s_testSource) {
+        fail("could not read test source file");
+        free(filepath);
+        return NULL;
+    }
+    ts = tokenstream_open(filepath, s_testSource);
+    free(filepath);
+    return ts;
+}
+
+Module* test_get_ast(void) {
+    TokenStream* ts = tokenstream_get_test();
+    if (!ts) return NULL;
+    return parser_parse(ts);
+}
+
+void assert_log(const char* expected, const char* msg) {
+    assert_str(expected, s_logOutput, msg);
+}
+
 void assert_log_file(const char* msg) {
     char* filepath = format_string("v0/tests/%s.log", s_currentTestName);
     const char* generate;
@@ -109,28 +144,6 @@ void assert_false(bool condition, const char* msg) {
     }
 }
 
-TokenStream* tokenstream_get_test(void) {
-    char* filepath = NULL;
-    TokenStream* ts = NULL;
-
-    filepath = format_string("v0/tests/%s.c2", s_currentTestName);
-    if (!filepath) {
-        fail("out of memory");
-        return NULL;
-    }
-    
-    if (s_testSource) free(s_testSource);
-    s_testSource = read_file_content(filepath);
-    if (!s_testSource) {
-        fail("could not read test source file");
-        free(filepath);
-        return NULL;
-    }
-    ts = tokenstream_open(filepath, s_testSource);
-    free(filepath);
-    return ts;
-}
-
 static void log_append(const char* msg) {
     size_t oldLen = s_logOutput ? strlen(s_logOutput) : 0;
     size_t newLen = oldLen + strlen(msg) + 1;
diff --git a/v0/test.h b/v0/test.h
index ca74f1b..e6d15c2 100644
--- a/v0/test.h
+++ b/v0/test.h
@@ -5,6 +5,7 @@
 #define TEST_H
 
 #include "token.h"
+#include "ast.h"
 
 typedef void (*Test)(void);
 
@@ -35,6 +36,17 @@ void assert_not_null(void* ptr, const char* msg);
  */
 void assert_str(const char* expected, const char* actual, const char* msg);
 
+/**
+ * Asserts that a string has the expected value.
+ * 
+ * Calls `fail` if the assertion does not hold.
+ * 
+ * @param expected The expected value. This is typically a string literal.
+ * @param actual The actual value. This is typically an expression.
+ * @param msg The message to print if these do not match.
+ */
+void assert_string(const char* expected, String actual, const char* msg);
+
 /**
  * Asserts that the logged output matches the expected value.
  */
@@ -66,7 +78,17 @@ void assert_false(bool condition, const char* msg);
 /**
  * Get the token stream used for this test.
  * It reads from the `v0/tests/xyz.c2` file, where xyz is the test name.
+ * 
+ * At the end of the test, the tokenstream will be freed automatically by the test harness.
  */
-TokenStream* tokenstream_get_test(void);
+TokenStream* test_get_tokenstream(void);
+
+/**
+ * Gets a parsed module for the this test.
+ * It reads from the `v0/tests/xyz.c2` file, where xyz is the test name.
+ * 
+ * At the end of the test, the AST will be freed automatically by the test harness.
+ */
+Module* test_get_ast(void);
 
 #endif
diff --git a/v0/test_parser.c b/v0/test_parser.c
index c9767e9..dbb2e97 100644
--- a/v0/test_parser.c
+++ b/v0/test_parser.c
@@ -6,16 +6,10 @@
 static void test_parser_module_name(void) {
 	TokenStream* ts = tokenstream_open("test.c", "module my_module;");
 	Module* m = parser_parse(ts);
-    char* buf;
 
 	assert_not_null(m, "expected module to be parsed");
-    buf = malloc(m->name.text.length + 1);
-    memcpy(buf, m->name.text.data, m->name.text.length);
-    buf[m->name.text.length] = '\0';
-	assert_str("my_module", buf, "expected name 'my_module'");
-    free(buf);
-
-	parser_free(m);
+	assert_string("my_module", m->name.text, "expected name 'my_module'");
+    parser_free(m);
 	tokenstream_close(ts);
 }
 
@@ -62,49 +56,29 @@ static void test_parser_bad_import_name(void) {
 static void test_parser_imports(void) {
 	TokenStream* ts = tokenstream_open("test.c", "module my_module; import other_module;");
 	Module* m = parser_parse(ts);
-    char* buf;
-
+	
 	assert_not_null(m, "expected module to be parsed");
-    buf = malloc(m->name.text.length + 1);
-    memcpy(buf, m->name.text.data, m->name.text.length);
-    buf[m->name.text.length] = '\0';
-	assert_str("my_module", buf, "expected name 'my_module'");
-    free(buf);
+    assert_string("my_module", m->name.text, "expected name 'my_module'");
 	
 	assert_not_null(m->imports, "expected imports to be parsed");
 	assert_int(1, (int)m->import_count, "expected one import");
-    buf = malloc(m->imports[0].module_name.text.length + 1);
-    memcpy(buf, m->imports[0].module_name.text.data, m->imports[0].module_name.text.length);
-    buf[m->imports[0].module_name.text.length] = '\0';
-	assert_str("other_module", buf, "expected import name 'other_module'");
-    free(buf);
+    assert_string("other_module", m->imports[0].module_name.text, "expected import name 'other_module'");
 	assert_false(m->imports[0].is_public, "expected import to not be public");
-
-	parser_free(m);
+    parser_free(m);
 	tokenstream_close(ts);
 }
 
 static void test_parser_public_imports(void) {
 	TokenStream* ts = tokenstream_open("test.c", "module my_module; import public other_module;");
 	Module* m = parser_parse(ts);
-    char* buf;
-
+	
 	assert_not_null(m, "expected module to be parsed");
-    buf = malloc(m->name.text.length + 1);
-    memcpy(buf, m->name.text.data, m->name.text.length);
-    buf[m->name.text.length] = '\0';
-	assert_str("my_module", buf, "expected name 'my_module'");
-    free(buf);
+    assert_string("my_module", m->name.text, "expected name 'my_module'");
 	
 	assert_not_null(m->imports, "expected imports to be parsed");
 	assert_int(1, (int)m->import_count, "expected one import");
-    buf = malloc(m->imports[0].module_name.text.length + 1);
-    memcpy(buf, m->imports[0].module_name.text.data, m->imports[0].module_name.text.length);
-    buf[m->imports[0].module_name.text.length] = '\0';
-	assert_str("other_module", buf, "expected import name 'other_module'");
-    free(buf);
+    assert_string("other_module", m->imports[0].module_name.text, "expected import name 'other_module'");
 	assert_true(m->imports[0].is_public, "expected import to be public");
-
-	parser_free(m);
+    parser_free(m);
 	tokenstream_close(ts);
 }
diff --git a/v0/types.h b/v0/types.h
new file mode 100644
index 0000000..f96466a
--- /dev/null
+++ b/v0/types.h
@@ -0,0 +1,9 @@
+/**
+ * Contains runtime information about types.
+ */
+#ifndef TYPES_H
+#define TYPES_H
+
+
+
+#endif