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The practice of component interface testing can be used to check the handling of data passed between various units, or subsystem components, beyond full integration testing between those units. The data being passed can be considered as "message packets" and the range or data types can be checked, for data generated from one unit, and tested for validity before being passed into another unit. One option for interface testing is to keep a separate log file of data items being passed, often with a timestamp logged to allow analysis of thousands of cases of data passed between units for days or weeks. Tests can include checking the handling of some extreme data values while other interface variables are passed as normal values. Unusual data values in an interface can help explain unexpected performance in the next unit. Component interface testing is a variation of black-box testing, with the focus on the data values beyond just the related actions of a subsystem component.
Usual data values in an interface can be used to explain what?
A: unanswerable

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The Cubs successfully defended their National League Central title in 2008, going to the postseason in consecutive years for the first time since 1906–08. The offseason was dominated by three months of unsuccessful trade talks with the Orioles involving 2B Brian Roberts, as well as the signing of Chunichi Dragons star Kosuke Fukudome. The team recorded their 10,000th win in April, while establishing an early division lead. Reed Johnson and Jim Edmonds were added early on and Rich Harden was acquired from the Oakland Athletics in early July. The Cubs headed into the All-Star break with the N.L.'s best record, and tied the league record with eight representatives to the All-Star game, including catcher Geovany Soto, who was named Rookie of the Year. The Cubs took control of the division by sweeping a four-game series in Milwaukee. On September 14, in a game moved to Miller Park due to Hurricane Ike, Zambrano pitched a no-hitter against the Astros, and six days later the team clinched by beating St. Louis at Wrigley. The club ended the season with a 97–64 record and met Los Angeles in the NLDS. The heavily favored Cubs took an early lead in Game 1, but James Loney's grand slam off Ryan Dempster changed the series' momentum. Chicago committed numerous critical errors and were outscored 20–6 in a Dodger sweep, which provided yet another sudden ending.
Who was acquired from the Oakland Athletics in early July?
A: Rich Harden

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Roman camps followed a standard pattern for defense and religious ritual; in effect they were Rome in miniature. The commander's headquarters stood at the centre; he took the auspices on a dais in front. A small building behind housed the legionary standards, the divine images used in religious rites and in the Imperial era, the image of the ruling emperor. In one camp, this shrine is even called Capitolium. The most important camp-offering appears to have been the suovetaurilia performed before a major, set battle. A ram, a boar and a bull were ritually garlanded, led around the outer perimeter of the camp (a lustratio exercitus) and in through a gate, then sacrificed: Trajan's column shows three such events from his Dacian wars. The perimeter procession and sacrifice suggest the entire camp as a divine templum; all within are purified and protected.
For what purpose were Roman camps arranged?
A: defense and religious ritual

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In the late 14th century, the Songhai gradually gained independence from the Mali Empire and expanded, ultimately subsuming the entire eastern portion of the Mali Empire. The Songhai Empire's eventual collapse was largely the result of a Moroccan invasion in 1591, under the command of Judar Pasha. The fall of the Songhai Empire marked the end of the region's role as a trading crossroads. Following the establishment of sea routes by the European powers, the trans-Saharan trade routes lost significance.
The Sonhgai Empire's demise was due to what invasion?
A:
Moroccan invasion in 1591