The Codecov Delta (aka Codecov ∆) is our syntax for expressing coverage metrics and their impact on the scope of what is being measured.

There are three data points in the Codecov Delta:
1: The absolute scope. e.g., 35%.
2: The relative scope. e.g., <72%>.
3: The change in coverage. e.g., (+4%).

Absolute

The entire project's coverage.

Read as "The entire project coverage is 35%."

Relative

Coverage concerning only lines adjusted in the commit diff (aka the diff coverage)

Read as "The lines I changed in this commit are 72% covered."
Also read as "The coverage of this commit's diff is 72%."

Change

The amount of gain or loss of coverage when compared to the commit's parent.

Read as "This commit increased coverage by 4%."

The character ø represents "not affected" or "no change". This value could be found in the <relative> and (change) block of the Coverage Delta.

When found in the <relative> block, it represents that the coverage diff was not concerning coverage. (e.g a commit that only adjusts lines not tracked by coverage.)

When found in the (change) block, it represents that coverage did not change. (e.g. 0% change. The commit did not affect project coverage.)

We use the Codecov Delta throughout the app. It expresses details for the entire project, flags, diffs, folders and files. It is important to understand the context of the delta.

The absolute, relative, and change metrics refer to the context. In the example below, the Codecov Delta appears in the file headers. The Delta's metrics concern only the file itself.