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在写单元测试前，首先进行复利程序代码的在结构上的修改，将显示与计算分隔开，目的是为了便于传入参数进行测试，并且重命名类的名字方便理解。
1 package ch1; 2 3 import java.util.InputMismatchException; 4 import java.util.Scanner; 5 6 public class Calculate { 7 static double capital=0; 8 static double rate=0; 9 static double C=0; 10 public static void main(String[] args) { 11 System.out.print("请选择求单利1,复利2,本金3,时间4,利率5,投资6,贷款月还款计算7,退出8"); 12 Scanner scanner = new Scanner(System.in); 13 int a = scanner.nextInt(); 14 switch (a) { 15 case 1: 16 simple_interest(); 17 break; 18 case 2: 19 compound_interest(); 20 break; 21 case 3: 22 capital(); 23 break; 24 case 4: 25 time(); 26 break; 27 case 5: 28 rate(); 29 break; 30 case 6: 31 invest(); 32 break; 33 case 7: 34 repayment(); 35 break; 36 case 8: 37 break; 38 default: 39 System.out.print("请重新输入"); 40 main(null); 41 scanner.close(); 42 //case 1:输入字符，负数 43 } 44 45 } 46 47 static void capital() { 48 // TODO Auto-generated method stub 49 Scanner scanner = new Scanner(System.in); 50 try { 51 System.out.print("请输入预期钱数"); 52 capital = Math.abs(scanner.nextDouble()); 53 System.out.print("请输入年利率"); 54 rate = Math.abs(scanner.nextDouble()); 55 System.out.print("请输入存入年限"); 56 C = Math.abs(scanner.nextInt()); 57 double D = 1; 58 for (int i = 1; i <= C; i++) { 59 D = D * (1 + rate); 60 } 61 System.out.println("本金" + String.format("%.4f", (capital / D))); 62 } catch (InputMismatchException e) { 63 capital(); 64 } 65 main(null); 66 scanner.close(); 67 } 68 69 static void compound_interest() { 70 Scanner scanner = new Scanner(System.in); 71 try { 72 System.out.print("请输入本金"); 73 double A = Math.abs(scanner.nextDouble()); 74 System.out.print("请输入年利率"); 75 double B = Math.abs(scanner.nextDouble()); 76 System.out.print("请输入存入年限"); 77 int C = Math.abs(scanner.nextInt()); 78 double D = 1; 79 for (int i = 1; i <= C; i++) { 80 D = D * (1 + B); 81 } 82 System.out.println("复利终值" + String.format("%.4f", (A * D))); 83 } catch (InputMismatchException e) { 84 compound_interest(); 85 } 86 main(null); 87 scanner.close(); 88 } 89 90 static void simple_interest() { 91 Scanner scanner = new Scanner(System.in); 92 try { 93 System.out.print("请输入本金"); 94 capital = Math.abs(scanner.nextDouble()); 95 System.out.print("请输入年利率"); 96 rate = Math.abs(scanner.nextDouble()); 97 System.out.print("请输入存入年限"); 98 C = Math.abs(scanner.nextInt()); 99 double D = 1; 100 D = capital * rate * C; 101 System.out.println("单利终值" + (capital + D)); 102 } catch (InputMismatchException e) { 103 simple_interest(); 104 } 105 main(null); 106 scanner.close(); 107 } 108 109 static void time() { 110 Scanner scanner = new Scanner(System.in); 111 try { 112 System.out.print("请输入本金"); 113 double A = Math.abs(scanner.nextDouble()); 114 System.out.print("请输入年利率"); 115 double B = Math.abs(scanner.nextDouble()); 116 System.out.print("请输入预期金额"); 117 double C = Math.abs(scanner.nextDouble()); 118 double D = 1; 119 double E = 1; 120 int i = 1; 121 122 while (true) { 123 D = D * (1 + B); 124 E = A * D; 125 if (E <= C) 126 i++; 127 else 128 break; 129 } 130 131 System.out.println("需" + i + "年"); 132 } catch (InputMismatchException e) { 133 time(); 134 } 135 main(null); 136 scanner.close(); 137 } 138 139 static void rate() { 140 Scanner scanner = new Scanner(System.in); 141 try { 142 System.out.print("请输入本金"); 143 double A = Math.abs(scanner.nextDouble()); 144 System.out.print("请输入预期金额"); 145 double B = Math.abs(scanner.nextDouble()); 146 System.out.print("请输入存入年限"); 147 double C = Math.abs(scanner.nextDouble()); 148 double D = 1; 149 D = Math.pow(B / A, 1 / C) - 1; 150 System.out.println("利率为" + String.format("%.4f", D)); 151 } catch (InputMismatchException e) { 152 rate(); 153 } 154 main(null); 155 scanner.close(); 156 } 157 158 static void invest() { 159 // TODO Auto-generated method stub 160 Scanner scanner = new Scanner(System.in); 161 try { 162 System.out.print("请输入投资额"); 163 double A = Math.abs(scanner.nextDouble()); 164 System.out.print("请输入年利率"); 165 double B = Math.abs(scanner.nextDouble()); 166 System.out.print("请输入存入年限"); 167 int C = Math.abs(scanner.nextInt()); 168 double D = 0; 169 for (int i = 1; i <= C; i++) { 170 D = D + A; 171 D = D * (1 + B); 172 } 173 System.out.println("最终获利" + String.format("%.4f", D)); 174 } catch (InputMismatchException e) { 175 invest(); 176 } 177 main(null); 178 scanner.close(); 179 } 180 181 static void repayment() { 182 // TODO 自动生成的方法存根 183 Scanner scanner = new Scanner(System.in); 184 try { 185 System.out.print("请输入贷款额"); 186 double A = Math.abs(scanner.nextDouble()); 187 System.out.print("请输入贷款利率"); 188 double B = Math.abs(scanner.nextDouble()); 189 System.out.print("请输入贷款年限"); 190 int C = Math.abs(scanner.nextInt()); 191 double D = 0; 192 for (int i = 1; i <= C; i++) { 193 D = A * Math.pow(1.0 + B, C); 194 } 195 double Repayment = D / (C * 12); 196 double interest = A * B * C; 197 double sum = A + interest; 198 double Repayment1 = sum / (C * 12); 199 System.out.println("每月需要还款(单利)" + Repayment1); 200 System.out.println("每月需要还款(复利)" + String.format("%.4f", Repayment)); 201 } catch (InputMismatchException e) { 202 repayment(); 203 } 204 main(null); 205 scanner.close(); 206 } 207 208 }
在单元测试中，共分两个场景。
1.给定数值给函数，判断结果是否与预期一致。如下图
2.进行输入异常判断，由于还不了解如何对用户输入进行自动测试，因此通过手动输入字符空格等进行测试。
所有代码都已上传至https://github.com/zhengmingze/java.git
文件名分别为：calculator.java ,calculatorTest.java
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原文地址：http://www.cnblogs.com/95mz/p/5332690.html
