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29 
30 // A sample program demonstrating using Google C++ testing framework.
31 //
32 // Author: wan@google.com (Zhanyong Wan)
33 
34 
35 // This sample shows how to write a simple unit test for a function,
36 // using Google C++ testing framework.
37 //
38 // Writing a unit test using Google C++ testing framework is easy as 1-2-3:
39 
40 
41 // Step 1. Include necessary header files such that the stuff your
42 // test logic needs is declared.
43 //
44 // Don't forget gtest.h, which declares the testing framework.
45 
46 #include <limits.h>
47 #include "sample1.h"
48 #include "gtest/gtest.h"
49 
50 
51 // Step 2. Use the TEST macro to define your tests.
52 //
53 // TEST has two parameters: the test case name and the test name.
54 // After using the macro, you should define your test logic between a
55 // pair of braces.  You can use a bunch of macros to indicate the
56 // success or failure of a test.  EXPECT_TRUE and EXPECT_EQ are
57 // examples of such macros.  For a complete list, see gtest.h.
58 //
59 // <TechnicalDetails>
60 //
61 // In Google Test, tests are grouped into test cases.  This is how we
62 // keep test code organized.  You should put logically related tests
63 // into the same test case.
64 //
65 // The test case name and the test name should both be valid C++
66 // identifiers.  And you should not use underscore (_) in the names.
67 //
68 // Google Test guarantees that each test you define is run exactly
69 // once, but it makes no guarantee on the order the tests are
70 // executed.  Therefore, you should write your tests in such a way
71 // that their results don't depend on their order.
72 //
73 // </TechnicalDetails>
74 
75 
76 // Tests Factorial().
77 
78 // Tests factorial of negative numbers.
TEST(FactorialTest,Negative)79 TEST(FactorialTest, Negative) {
80   // This test is named "Negative", and belongs to the "FactorialTest"
81   // test case.
82   EXPECT_EQ(1, Factorial(-5));
83   EXPECT_EQ(1, Factorial(-1));
84   EXPECT_GT(Factorial(-10), 0);
85 
86   // <TechnicalDetails>
87   //
88   // EXPECT_EQ(expected, actual) is the same as
89   //
90   //   EXPECT_TRUE((expected) == (actual))
91   //
92   // except that it will print both the expected value and the actual
93   // value when the assertion fails.  This is very helpful for
94   // debugging.  Therefore in this case EXPECT_EQ is preferred.
95   //
96   // On the other hand, EXPECT_TRUE accepts any Boolean expression,
97   // and is thus more general.
98   //
99   // </TechnicalDetails>
100 }
101 
102 // Tests factorial of 0.
TEST(FactorialTest,Zero)103 TEST(FactorialTest, Zero) {
104   EXPECT_EQ(1, Factorial(0));
105 }
106 
107 // Tests factorial of positive numbers.
TEST(FactorialTest,Positive)108 TEST(FactorialTest, Positive) {
109   EXPECT_EQ(1, Factorial(1));
110   EXPECT_EQ(2, Factorial(2));
111   EXPECT_EQ(6, Factorial(3));
112   EXPECT_EQ(40320, Factorial(8));
113 }
114 
115 
116 // Tests IsPrime()
117 
118 // Tests negative input.
TEST(IsPrimeTest,Negative)119 TEST(IsPrimeTest, Negative) {
120   // This test belongs to the IsPrimeTest test case.
121 
122   EXPECT_FALSE(IsPrime(-1));
123   EXPECT_FALSE(IsPrime(-2));
124   EXPECT_FALSE(IsPrime(INT_MIN));
125 }
126 
127 // Tests some trivial cases.
TEST(IsPrimeTest,Trivial)128 TEST(IsPrimeTest, Trivial) {
129   EXPECT_FALSE(IsPrime(0));
130   EXPECT_FALSE(IsPrime(1));
131   EXPECT_TRUE(IsPrime(2));
132   EXPECT_TRUE(IsPrime(3));
133 }
134 
135 // Tests positive input.
TEST(IsPrimeTest,Positive)136 TEST(IsPrimeTest, Positive) {
137   EXPECT_FALSE(IsPrime(4));
138   EXPECT_TRUE(IsPrime(5));
139   EXPECT_FALSE(IsPrime(6));
140   EXPECT_TRUE(IsPrime(23));
141 }
142 
143 // Step 3. Call RUN_ALL_TESTS() in main().
144 //
145 // We do this by linking in src/gtest_main.cc file, which consists of
146 // a main() function which calls RUN_ALL_TESTS() for us.
147 //
148 // This runs all the tests you've defined, prints the result, and
149 // returns 0 if successful, or 1 otherwise.
150 //
151 // Did you notice that we didn't register the tests?  The
152 // RUN_ALL_TESTS() macro magically knows about all the tests we
153 // defined.  Isn't this convenient?
154