diff options
Diffstat (limited to 'src/sort/search_test.go')
-rw-r--r-- | src/sort/search_test.go | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/src/sort/search_test.go b/src/sort/search_test.go index f06897ee21..49813eaecb 100644 --- a/src/sort/search_test.go +++ b/src/sort/search_test.go @@ -7,6 +7,7 @@ package sort_test import ( "runtime" . "sort" + stringspkg "strings" "testing" ) @@ -57,6 +58,80 @@ func TestSearch(t *testing.T) { } } +func TestFind(t *testing.T) { + str1 := []string{"foo"} + str2 := []string{"ab", "ca"} + str3 := []string{"mo", "qo", "vo"} + str4 := []string{"ab", "ad", "ca", "xy"} + + // slice with repeating elements + strRepeats := []string{"ba", "ca", "da", "da", "da", "ka", "ma", "ma", "ta"} + + // slice with all element equal + strSame := []string{"xx", "xx", "xx"} + + tests := []struct { + data []string + target string + wantPos int + wantFound bool + }{ + {[]string{}, "foo", 0, false}, + {[]string{}, "", 0, false}, + + {str1, "foo", 0, true}, + {str1, "bar", 0, false}, + {str1, "zx", 1, false}, + + {str2, "aa", 0, false}, + {str2, "ab", 0, true}, + {str2, "ad", 1, false}, + {str2, "ca", 1, true}, + {str2, "ra", 2, false}, + + {str3, "bb", 0, false}, + {str3, "mo", 0, true}, + {str3, "nb", 1, false}, + {str3, "qo", 1, true}, + {str3, "tr", 2, false}, + {str3, "vo", 2, true}, + {str3, "xr", 3, false}, + + {str4, "aa", 0, false}, + {str4, "ab", 0, true}, + {str4, "ac", 1, false}, + {str4, "ad", 1, true}, + {str4, "ax", 2, false}, + {str4, "ca", 2, true}, + {str4, "cc", 3, false}, + {str4, "dd", 3, false}, + {str4, "xy", 3, true}, + {str4, "zz", 4, false}, + + {strRepeats, "da", 2, true}, + {strRepeats, "db", 5, false}, + {strRepeats, "ma", 6, true}, + {strRepeats, "mb", 8, false}, + + {strSame, "xx", 0, true}, + {strSame, "ab", 0, false}, + {strSame, "zz", 3, false}, + } + + for _, tt := range tests { + t.Run(tt.target, func(t *testing.T) { + cmp := func(i int) int { + return stringspkg.Compare(tt.target, tt.data[i]) + } + + pos, found := Find(len(tt.data), cmp) + if pos != tt.wantPos || found != tt.wantFound { + t.Errorf("Find got (%v, %v), want (%v, %v)", pos, found, tt.wantPos, tt.wantFound) + } + }) + } +} + // log2 computes the binary logarithm of x, rounded up to the next integer. // (log2(0) == 0, log2(1) == 0, log2(2) == 1, log2(3) == 2, etc.) func log2(x int) int { @@ -158,3 +233,34 @@ func TestSearchExhaustive(t *testing.T) { } } } + +// Abstract exhaustive test for Find. +func TestFindExhaustive(t *testing.T) { + // Test Find for different sequence sizes and search targets. + // For each size, we have a (unmaterialized) sequence of integers: + // 2,4...size*2 + // And we're looking for every possible integer between 1 and size*2 + 1. + for size := 0; size <= 100; size++ { + for x := 1; x <= size*2+1; x++ { + var wantFound bool + var wantPos int + + cmp := func(i int) int { + // Encodes the unmaterialized sequence with elem[i] == (i+1)*2 + return x - (i+1)*2 + } + pos, found := Find(size, cmp) + + if x%2 == 0 { + wantPos = x/2 - 1 + wantFound = true + } else { + wantPos = x / 2 + wantFound = false + } + if found != wantFound || pos != wantPos { + t.Errorf("Find(%d, %d): got (%v, %v), want (%v, %v)", size, x, pos, found, wantPos, wantFound) + } + } + } +} |