initial commit

java/base/Asserts.java

@@ -0,0 +1,84 @@
+package base;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Locale;
+import java.util.Objects;
+
+/**
+ * @author Georgiy Korneev (kgeorgiy@kgeorgiy.info)
+ */
+@SuppressWarnings("StaticMethodOnlyUsedInOneClass")
+public final class Asserts {
+    static {
+        Locale.setDefault(Locale.US);
+    }
+
+    private Asserts() {
+    }
+
+    public static void assertEquals(final String message, final Object expected, final Object actual) {
+        final String reason = String.format("%s:%n     expected `%s`,%n       actual `%s`",
+                message, toString(expected), toString(actual));
+        assertTrue(reason, Objects.deepEquals(expected, actual));
+    }
+
+    public static String toString(final Object value) {
+        if (value != null && value.getClass().isArray()) {
+            final String result = Arrays.deepToString(new Object[]{value});
+            return result.substring(1, result.length() - 1);
+        } else {
+            return Objects.toString(value);
+        }
+    }
+
+    public static <T> void assertEquals(final String message, final List<T> expected, final List<T> actual) {
+        for (int i = 0; i < Math.min(expected.size(), actual.size()); i++) {
+            assertEquals(message + ":" + (i + 1), expected.get(i), actual.get(i));
+        }
+        assertEquals(message + ": Number of items", expected.size(), actual.size());
+    }
+
+    public static void assertTrue(final String message, final boolean value) {
+        if (!value) {
+            throw error("%s", message);
+        }
+    }
+
+    public static void assertEquals(final String message, final double expected, final double actual, final double precision) {
+        assertTrue(
+                String.format("%s: Expected %.12f, found %.12f", message, expected, actual),
+                isEqual(expected, actual, precision)
+        );
+    }
+
+    public static boolean isEqual(final double expected, final double actual, final double precision) {
+        final double error = Math.abs(actual - expected);
+        return error <= precision
+               || error <= precision * Math.abs(expected)
+               || !Double.isFinite(expected)
+               || Math.abs(expected) > 1e100
+               || Math.abs(expected) < precision && !Double.isFinite(actual);
+    }
+
+    public static void assertSame(final String message, final Object expected, final Object actual) {
+        assertTrue(String.format("%s: expected same objects: %s and %s", message, expected, actual), expected == actual);
+    }
+
+    public static void checkAssert(final Class<?> c) {
+        if (!c.desiredAssertionStatus()) {
+            throw error("You should enable assertions by running 'java -ea %s'", c.getName());
+        }
+    }
+
+    public static AssertionError error(final String format, final Object... args) {
+        final String message = String.format(format, args);
+        return args.length > 0 && args[args.length - 1] instanceof Throwable
+               ? new AssertionError(message, (Throwable) args[args.length - 1])
+               : new AssertionError(message);
+    }
+
+    public static void printStackTrace(final String message) {
+        new Exception(message).printStackTrace(System.out);
+    }
+}