void assertLinesMatchWithFastForward()

in junit-jupiter-api/src/main/java/org/junit/jupiter/api/AssertLinesMatch.java [116:183]
50 lines of code
14 McCabe index (conditional complexity)

		void assertLinesMatchWithFastForward() {
			Deque<String> expectedDeque = new ArrayDeque<>(expectedLines);
			Deque<String> actualDeque = new ArrayDeque<>(actualLines);

			main: while (!expectedDeque.isEmpty()) {
				String expectedLine = expectedDeque.pop();
				int expectedLineNumber = expectedLines.size() - expectedDeque.size(); // 1-based line number
				// trivial case: no more actual lines available
				if (actualDeque.isEmpty()) {
					fail("expected line #%d:`%s` not found - actual lines depleted", expectedLineNumber,
						snippet(expectedLine));
				}

				String actualLine = actualDeque.peek();
				// trivial case: take the fast path when they simply match
				if (matches(expectedLine, actualLine)) {
					actualDeque.pop();
					continue; // main
				}

				// fast-forward marker found in expected line: fast-forward actual line...
				if (isFastForwardLine(expectedLine)) {
					int fastForwardLimit = parseFastForwardLimit(expectedLine);

					// trivial case: fast-forward marker was in last expected line
					if (expectedDeque.isEmpty()) {
						int actualRemaining = actualDeque.size();
						// no limit given or perfect match? we're done.
						if (fastForwardLimit == Integer.MAX_VALUE || fastForwardLimit == actualRemaining) {
							return;
						}
						fail("terminal fast-forward(%d) error: fast-forward(%d) expected", fastForwardLimit,
							actualRemaining);
					}

					// fast-forward limit was given: use it
					if (fastForwardLimit != Integer.MAX_VALUE) {
						// fast-forward now: actualDeque.pop(fastForwardLimit)
						for (int i = 0; i < fastForwardLimit; i++) {
							actualDeque.pop();
						}
						continue; // main
					}

					// peek next expected line
					expectedLine = expectedDeque.peek();
					// fast-forward "unlimited": until next match
					while (true) {
						if (actualDeque.isEmpty()) {
							fail("fast-forward(∞) didn't find: `%s`", snippet(expectedLine));
						}
						if (matches(expectedLine, actualDeque.peek())) {
							continue main;
						}
						actualDeque.pop();
					}
				}

				int actualLineNumber = actualLines.size() - actualDeque.size() + 1; // 1-based line number
				fail("expected line #%d doesn't match actual line #%d%n" + "\texpected: `%s`%n" + "\t  actual: `%s`",
					expectedLineNumber, actualLineNumber, expectedLine, actualLine);
			}

			// after math
			if (!actualDeque.isEmpty()) {
				fail("more actual lines than expected: %d", actualDeque.size());
			}
		}