[Date] Implement %y year without century parser / formatter; respect digits that are below maximum format length

internal/func_time_parser_test.go

@@ -0,0 +1,93 @@
+package internal
+
+import "testing"
+
+func TestTimeParser(t *testing.T) {
+	for _, test := range []struct {
+		name             string
+		text             []rune
+		minValue         int64
+		maxValue         int64
+		expectedProgress int
+		expectedResult   int
+		expectedErr      string
+	}{
+		{
+			name:             "single digit but multiple allowed; non-digit character terminates",
+			text:             []rune{'2', '/'},
+			minValue:         1,
+			maxValue:         12,
+			expectedResult:   2,
+			expectedProgress: 1,
+		},
+		{
+			name:             "multiple digits; non-digit character terminates",
+			text:             []rune{'1', '2', '/'},
+			minValue:         1,
+			maxValue:         12,
+			expectedResult:   12,
+			expectedProgress: 2,
+		},
+		{
+			name:             "leading zero digit but multiple allowed; non-digit character terminates",
+			text:             []rune{'0', '2', '/'},
+			minValue:         1,
+			maxValue:         12,
+			expectedResult:   2,
+			expectedProgress: 2,
+		},
+
+		{
+			name:             "leading zero digit but multiple allowed; non-digit character terminates",
+			text:             []rune{'0', '0', '2', '/'},
+			minValue:         1,
+			maxValue:         9999,
+			expectedResult:   2,
+			expectedProgress: 3,
+		},
+		{
+			name:        "multiple digits but exceeds limit; non-digit character terminates",
+			text:        []rune{'2', '2', '/'},
+			minValue:    1,
+			maxValue:    12,
+			expectedErr: "part [22] is greater than maximum value [12]",
+		},
+		{
+			name:        "multiple digits but lower than start bound; non-digit character terminates",
+			text:        []rune{'0', '0', '/'},
+			minValue:    1,
+			maxValue:    12,
+			expectedErr: "part [0] is less than minimum value [1]",
+		},
+		{
+			name:             "multiple digits but lower than start bound; non-digit character terminates",
+			text:             []rune{'4', '-'},
+			minValue:         1,
+			maxValue:         12,
+			expectedResult:   4,
+			expectedProgress: 1,
+		},
+	} {
+
+		t.Run(test.name, func(t *testing.T) {
+			progress, result, err := parseDigitRespectingOptionalPlaces(test.text, test.minValue, test.maxValue)
+			if err != nil {
+				if test.expectedErr != err.Error() {
+					t.Fatalf("unexpected error message: expected [%s] but got [%s]", test.expectedErr, err.Error())
+				} else {
+					// expected error occurred, consider test successful
+					return
+				}
+			}
+
+			if progress != test.expectedProgress {
+				t.Fatalf("unexpected progress: expected [%d] but got [%d]", test.expectedProgress, progress)
+			}
+
+			if result != int64(test.expectedResult) {
+				t.Fatalf("unexpected result: expected [%d] but got [%d]", test.expectedResult, result)
+			}
+
+		})
+	}
+}