我目前正在开发一个文本格式化程序项目，我从LineAssembler类开始。但是，我们需要在编写任何代码之前编写单元测试，而且我有点卡住了。
请问有人会点灯吗？我还将PageAssembler骨架及其给定的单元测试作为参考。谢谢！
package tex61;
import java.util.ArrayList;
import static tex61.FormatException.error;
/** An object that receives a sequence of words of text and formats
* the words into filled and justified text lines that are sent to a receiver.
*/
class LineAssembler {
/** A new, empty line assembler with default settings of all
* parameters, sending finished lines to PAGES. */
LineAssembler(PageAssembler pages) {
_pages = pages;
// FIXME
}
/** Add TEXT to the word currently being built. */
void addText(String text) {
// FIXME
}
/** Finish the current word, if any, and add to words being accumulated. */
void finishWord() {
// FIXME
}
/** Add WORD to the formatted text. */
void addWord(String word) {
// FIXME
}
/** Add LINE to our output, with no preceding paragraph skip. There must
* not be an unfinished line pending. */
void addLine(String line) {
// FIXME
}
/** Set the current indentation to VAL. VAL >= 0. */
void setIndentation(int val) {
// FIXME
}
/** Set the current paragraph indentation to VAL. VAL >= 0. */
void setParIndentation(int val) {
// FIXME
}
/** Set the text width to VAL, where VAL >= 0. */
void setTextWidth(int val) {
// FIXME
}
/** Iff ON, set fill mode. */
void setFill(boolean on) {
// FIXME
}
/** Iff ON, set justify mode (which is active only when filling is
* also on). */
void setJustify(boolean on) {
// FIXME
}
/** Set paragraph skip to VAL. VAL >= 0. */
void setParSkip(int val) {
// FIXME
}
/** Set page height to VAL > 0. */
void setTextHeight(int val) {
// FIXME
}
/** Process the end of the current input line. No effect if
* current line accumulator is empty or in fill mode. Otherwise,
* adds a new complete line to the finished line queue and clears
* the line accumulator. */
void newLine() {
// FIXME
}
/** If there is a current unfinished paragraph pending, close it
* out and start a new one. */
void endParagraph() {
// FIXME
}
/** Transfer contents of _words to _pages, adding INDENT characters of
* indentation, and a total of SPACES spaces between words, evenly
* distributed. Assumes _words is not empty. Clears _words and _chars. */
private void emitLine(int indent, int spaces) {
// FIXME
}
/** If the line accumulator is non-empty, justify its current
* contents, if needed, add a new complete line to _pages,
* and clear the line accumulator. LASTLINE indicates the last line
* of a paragraph. */
private void outputLine(boolean lastLine) {
// FIXME
}
/** Destination given in constructor for formatted lines. */
private final PageAssembler _pages;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~
package tex61;
import static tex61.FormatException.error;
/** A PageAssembler accepts complete lines of text (minus any
* terminating newlines) and turns them into pages, adding form
* feeds as needed. It prepends a form feed (Control-L or ASCII 12)
* to the first line of each page after the first. By overriding the
* 'write' method, subtypes can determine what is done with
* the finished lines.
*/
abstract class PageAssembler {
private int _textHeight;
static final int UNLIMITED = Integer.MAX_VALUE;
/** Create a new PageAssembler. Initially, its text height is unlimited.
* It prepends a form feed character to the first line of each page
* except the first. */
PageAssembler() {
_textHeight = UNLIMITED;
// FIXME
}
/** Add LINE to the current page, starting a new page with it if
* the previous page is full. A null LINE indicates a skipped line,
* and has no effect at the top of a page. */
void addLine(String line) {
// FIXME
}
/** Set text height to VAL, where VAL > 0. */
void setTextHeight(int val) {
if(val > 0) {
_textHeight = val;
}
// FIXME
}
/** Perform final disposition of LINE, as determined by the
* concrete subtype. */
abstract void write(String line);
// FIXME
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
package tex61;
import java.io.PrintWriter;
/** A PageAssembler that sends lines immediately to a PrintWriter, with
* terminating newlines.
*/
class PagePrinter extends PageAssembler {
/** A new PagePrinter that sends lines to OUT. */
PagePrinter(PrintWriter out) {
// FIXME
}
/** Print LINE to my output. */
@Override
void write(String line) {
// FIXME
}
// FIXME
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
package tex61;
import java.util.List;
import java.util.ArrayList;
import java.io.StringWriter;
import java.io.PrintWriter;
import org.junit.Test;
import static org.junit.Assert.*;
/** Unit tests of PageAssemblers.*/
public class PageAssemblerTest {
private static final String NL = System.getProperty("line.separator");
private void setupWriter() {
output = new StringWriter();
writer = new PrintWriter(output);
}
private void setupCollector() {
outList = new ArrayList<>();
}
private void makeTestLines(int n) {
testLines = new ArrayList<>();
for (int i = 0; i < n; i += 1) {
testLines.add("Line " + i);
}
}
private void writeTestLines() {
for (String L : testLines) {
pages.addLine(L);
}
}
private String joinLines() {
StringBuilder S = new StringBuilder();
for (String L : testLines) {
S.append(L);
S.append(NL);
}
return S.toString();
}
@Test
public void testPrinterContents1() {
makeTestLines(20);
setupWriter();
pages = new PagePrinter(writer);
writeTestLines();
writer.close();
assertEquals("wrong contents: printer", joinLines(), output.toString());
}
@Test
public void testCollectorContents1() {
makeTestLines(20);
setupCollector();
pages = new PageCollector(outList);
writeTestLines();
assertEquals("wrong contents: collector", testLines, outList);
}
/** Collects output to a PrintWriter. */
private StringWriter output;
/** Collects output from a PageAssembler. */
private PrintWriter writer;
/** Lines of test data. */
private List<String> testLines;
/** Lines from a PageCollector. */
private List<String> outList;
/** Target PageAssembler. */
private PageAssembler pages;
}
答案 0 :(得分：1)
在实施解决方案之前编写单元测试用于
所以这更多的是为模块创建需求和设计应用程序。
当一个人遇到麻烦时，他可以打破这个规则并建立一个概念证明来理解他正在处理什么。然后重新考虑API，创建测试并将其原型调整为新API。当我创造一些我不熟悉或者不太复杂的东西时，我就是这样做的。