Unit test FastInput

Author: simonlindholm

content/various/FastInput.h

@@ -5,7 +5,7 @@
  * Description: Returns an integer. Usage requires your program to pipe in
  * input from file. Can replace calls to gc() with getchar\_unlocked() if extra
  * speed isn't necessary (60\% slowdown).
- * Status: tested on SPOJ INTEST
+ * Status: tested on SPOJ INTEST, unit tested
  * Time: About 5x as fast as cin/scanf.
  * Usage: ./a.out < input.txt
  */

stress-tests/various/FastInput.cpp

@@ -0,0 +1,72 @@
+#include "../utilities/template.h"
+
+#include "../../content/various/FastInput.h"
+#include <unistd.h>
+
+constexpr int BUF_SIZE = sizeof(gc.buf);
+
+string tempdirname;
+string tempfilename;
+
+void test(const string& s, vi ints = {}) {
+	gc.bc = gc.be = 0;
+	ofstream fout(tempfilename);
+	fout << s;
+	fout.close();
+	FILE* ret = freopen(tempfilename.c_str(), "r", stdin);
+	assert(ret == stdin);
+	if (ints.empty()) {
+		for (char c : s) {
+			int c2 = gc();
+			assert(c == c2);
+		}
+		assert(gc() == 0);
+		assert(gc() == 0);
+	} else {
+		for (int x : ints) {
+			int y = readInt();
+			if (x != y) {
+				cerr << "On input " << s << ", read " << y << " but expected " << x << endl;
+			}
+			assert(x == y);
+		}
+	}
+}
+
+int main() {
+	// Unit test, not stress test, but oh well.
+	char pattern[] = "/tmp/fastinputXXXXXX";
+	tempdirname = mkdtemp(pattern);
+	tempfilename = tempdirname + "/stdin.txt";
+
+	// First test that the getchar implementation is correct:
+	test("");
+	test("a");
+	test("ab");
+	string s;
+	for (int i = 0; i < BUF_SIZE; i++) s += (char)(i % 13);
+	test(s);
+	for (int i = 0; i < BUF_SIZE * 10 + 1; i++) s += (char)(i % 13);
+	test(s);
+	for (int i = 0; i < BUF_SIZE - 2; i++) s += (char)(i % 13);
+	test(s);
+	for (int i = 0; i < BUF_SIZE + 2; i++) {
+		assert(gc() == 0);
+	}
+
+	// Then test that readInt() is:
+	test("1", {1});
+	test("12", {12});
+	test("9\n", {9});
+	test("12 ", {12});
+	test("-23\n", {-23});
+	test(" -4", {-4});
+	test(" 5\n", {5});
+	test("1 -2 ", {1, -2});
+	test("  -34   56   ", {-34, 56});
+	test(" \t\r\n5 -2 ", {5});
+
+	unlink(tempfilename.c_str());
+	rmdir(tempdirname.c_str());
+	cout << "Tests passed!" << endl;
+}