Multiline assert support (fixes #5)

Author: jkschneider

README.md

@@ -1,7 +1,6 @@
 # Power Assertions for Java
 
 [![Build Status](https://travis-ci.org/jkschneider/java-power-assert.svg?branch=master)](https://travis-ci.org/jkschneider/java-power-assert)
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 [![Apache 2.0](https://img.shields.io/github/license/jkschneider/java-power-assert.svg)](http://www.apache.org/licenses/LICENSE-2.0)
 
 Power assertions (a.k.a. diagrammed assertions) augment your assertion failures with information about values produced during the evaluation of a condition, and presents them in an easily digestible form.

src/main/java/org/powerassert/JavacPowerAssertGenerator.java

@@ -231,9 +231,6 @@ else if(expr instanceof JCTree.JCUnary) {
 		else if(expr instanceof JCTree.JCMethodInvocation) {
 			JCTree.JCMethodInvocation method = (JCTree.JCMethodInvocation) expr;
 			return recordValue(
-					// oddly, methodSelect is expressed as a JCFieldAccess, and if we recurse through this expression,
-					// we will attempt to record the method name as a field access, which it is not... so do
-					// not recurse on method select
 					treeMaker.Apply(
 							method.typeargs,
 							recordAllValues(method.getMethodSelect(), expr),

src/main/java/org/powerassert/synthetic/ExpressionRenderer.java

@@ -37,11 +37,16 @@ public String render(RecordedExpression<?> recordedExpr) {
 			else break;
 		}
 
-		String intro = recordedExpr.getText().trim().replaceAll(";$", ""); // strip trailing semicolons
+		String intro = recordedExpr.getText().trim()
+				.replaceAll(";$", ""); // strip trailing semicolons
+		Map<Integer, Integer> strippedWhitespace = strippedWhitespaceUpToColumn(intro);
+		intro = intro.replaceAll("\n\\s+", " ");
+
 		List<String> lines = new ArrayList<>();
 
 		for(RecordedValue recordedValue: filterAndSortByAnchor(recordedExpr.getValues())) {
-			placeValue(lines, recordedValue.getValue(), recordedValue.getAnchor() - offset);
+			int offsetAnchor = recordedValue.getAnchor() - offset;
+			placeValue(lines, recordedValue.getValue(), offsetAnchor - strippedWhitespace.get(offsetAnchor));
 		}
 
 		lines.add(0, intro);
@@ -53,6 +58,33 @@ public String render(RecordedExpression<?> recordedExpr) {
 		return rendered;
 	}
 
+	/**
+	 * Help count how much newline and margin whitespace we have stripped up to a particular index so we know
+	 * how to offset anchors
+	 */
+	Map<Integer, Integer> strippedWhitespaceUpToColumn(String intro) {
+		Map<Integer, Integer> stripped = new TreeMap<>();
+		boolean countingWhitespace = false;
+		int col = 0;
+		int count = 0;
+		for (char c : intro.toCharArray()) {
+			if(c == '\n' && !countingWhitespace) {
+				// we don't count the first newline, as this will be replaced with a space
+				// (yielding the same column width in terms of characters)
+				countingWhitespace = true;
+			}
+			else if(countingWhitespace) {
+				if (Character.isWhitespace(c))
+					count++;
+				else
+					countingWhitespace = false;
+			}
+			stripped.put(col, count);
+			col++;
+		}
+		return stripped;
+	}
+
 	private Iterable<RecordedValue> filterAndSortByAnchor(List<RecordedValue> recordedValues) {
 		Map<Integer, RecordedValue> map = new TreeMap<>(new Comparator<Integer>() {
 			@Override

src/test/java/org/powerassert/AssertKeywordTest.java

@@ -16,7 +16,6 @@
 
 package org.powerassert;
 
-import org.junit.Before;
 import org.junit.Test;
 
 public class AssertKeywordTest extends AbstractAssertTest {

src/test/java/org/powerassert/MultilineAssertTest.java

@@ -0,0 +1,23 @@
+package org.powerassert;
+
+import org.junit.Test;
+
+public class MultilineAssertTest extends AbstractAssertTest {
+
+	@Test
+	public void chainedMethodCallsOnMultipleLines() {
+		java.compile(
+				"public class A {\n" +
+						"	@org.junit.Test public void test() {\n" +
+						"      assert \"abc\"\n" +
+						"			.substring(0)\n" +
+						"			.contains(\"d\");\n" +
+						"	}\n" +
+						"}\n");
+
+		testFailsWithMessage("A", "test",
+				"\"abc\" .substring(0) .contains(\"d\")",
+				"       |             |",
+				"       abc           false");
+	}
+}