feat(nix/readTree): add tests of the traversal logic in README r/2165

This should closely match the documented behaviour. It might still be
missing some edge cases of course.

Change-Id: I5c75fa045d5f3be8cf5eab787a02644500c14522
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2466
Reviewed-by: tazjin <mail@tazj.in>
Tested-by: BuildkiteCI

14 files changed, 46 insertions, 0 deletions

diff --git a/nix/readTree/tests/test-tree-traversal/default-nix/can-be-drv/default.nix b/nix/readTree/tests/test-tree-traversal/default-nix/can-be-drv/default.nix
new file mode 100644
index 000000000000..95d13d3c2750
--- /dev/null
+++ b/nix/readTree/tests/test-tree-traversal/default-nix/can-be-drv/default.nix
@@ -0,0 +1,7 @@
+{ ... }:
+derivation {
+  name = "im-a-drv";
+  system = builtins.currentSystem;
+  builder = "/bin/sh";
+  args = [ "-c" ''echo "" > $out'' ];
+}
diff --git a/nix/readTree/tests/test-tree-traversal/default-nix/can-be-drv/subdir/a.nix b/nix/readTree/tests/test-tree-traversal/default-nix/can-be-drv/subdir/a.nix
new file mode 100644
index 000000000000..2ee2d648f042
--- /dev/null
+++ b/nix/readTree/tests/test-tree-traversal/default-nix/can-be-drv/subdir/a.nix
@@ -0,0 +1,3 @@
+{ ... }:
+
+"Picked up through the drv"
diff --git a/nix/readTree/tests/test-tree-traversal/default-nix/default.nix b/nix/readTree/tests/test-tree-traversal/default-nix/default.nix
new file mode 100644
index 000000000000..6003b5398305
--- /dev/null
+++ b/nix/readTree/tests/test-tree-traversal/default-nix/default.nix
@@ -0,0 +1,5 @@
+{ ... }:
+
+{
+  no = "siblings should be read";
+}
diff --git a/nix/readTree/tests/test-tree-traversal/default-nix/no-merge/default.nix b/nix/readTree/tests/test-tree-traversal/default-nix/no-merge/default.nix
new file mode 100644
index 000000000000..c469533fbe5b
--- /dev/null
+++ b/nix/readTree/tests/test-tree-traversal/default-nix/no-merge/default.nix
@@ -0,0 +1,3 @@
+{ ... }:
+
+"I’m not merged with any children"
diff --git a/nix/readTree/tests/test-tree-traversal/default-nix/no-merge/subdir/a.nix b/nix/readTree/tests/test-tree-traversal/default-nix/no-merge/subdir/a.nix
new file mode 100644
index 000000000000..2008c2d2411f
--- /dev/null
+++ b/nix/readTree/tests/test-tree-traversal/default-nix/no-merge/subdir/a.nix
@@ -0,0 +1 @@
+"not accessible since parent default.nix is not an attrset"
diff --git a/nix/readTree/tests/test-tree-traversal/default-nix/sibling.nix b/nix/readTree/tests/test-tree-traversal/default-nix/sibling.nix
new file mode 100644
index 000000000000..8c57f2c16137
--- /dev/null
+++ b/nix/readTree/tests/test-tree-traversal/default-nix/sibling.nix
@@ -0,0 +1 @@
+"I’m left alone"
diff --git a/nix/readTree/tests/test-tree-traversal/default-nix/subdir/a.nix b/nix/readTree/tests/test-tree-traversal/default-nix/subdir/a.nix
new file mode 100644
index 000000000000..cf0ac2c8f3cf
--- /dev/null
+++ b/nix/readTree/tests/test-tree-traversal/default-nix/subdir/a.nix
@@ -0,0 +1,3 @@
+{ ... }:
+
+"but I’m picked up"
diff --git a/nix/readTree/tests/test-tree-traversal/no-skip-subtree/a/default.nix b/nix/readTree/tests/test-tree-traversal/no-skip-subtree/a/default.nix
new file mode 100644
index 000000000000..a586ce534ce2
--- /dev/null
+++ b/nix/readTree/tests/test-tree-traversal/no-skip-subtree/a/default.nix
@@ -0,0 +1,3 @@
+{ ... }:
+
+"am I subtree yet?"
diff --git a/nix/readTree/tests/test-tree-traversal/no-skip-subtree/b/c.nix b/nix/readTree/tests/test-tree-traversal/no-skip-subtree/b/c.nix
new file mode 100644
index 000000000000..06216c417be9
--- /dev/null
+++ b/nix/readTree/tests/test-tree-traversal/no-skip-subtree/b/c.nix
@@ -0,0 +1,3 @@
+{ ... }:
+
+"cool"
diff --git a/nix/readTree/tests/test-tree-traversal/no-skip-subtree/default.nix b/nix/readTree/tests/test-tree-traversal/no-skip-subtree/default.nix
new file mode 100644
index 000000000000..3d9f241cddb5
--- /dev/null
+++ b/nix/readTree/tests/test-tree-traversal/no-skip-subtree/default.nix
@@ -0,0 +1,5 @@
+{ ... }:
+
+{
+  but = "the default.nix is still read";
+}
diff --git a/nix/readTree/tests/test-tree-traversal/skip-subtree/.skip-subtree b/nix/readTree/tests/test-tree-traversal/skip-subtree/.skip-subtree
new file mode 100644
index 000000000000..87271ba5e101
--- /dev/null
+++ b/nix/readTree/tests/test-tree-traversal/skip-subtree/.skip-subtree
@@ -0,0 +1 @@
+this file makes subdirs be skipped, I hope
diff --git a/nix/readTree/tests/test-tree-traversal/skip-subtree/a/default.nix b/nix/readTree/tests/test-tree-traversal/skip-subtree/a/default.nix
new file mode 100644
index 000000000000..a586ce534ce2
--- /dev/null
+++ b/nix/readTree/tests/test-tree-traversal/skip-subtree/a/default.nix
@@ -0,0 +1,3 @@
+{ ... }:
+
+"am I subtree yet?"
diff --git a/nix/readTree/tests/test-tree-traversal/skip-subtree/b/c.nix b/nix/readTree/tests/test-tree-traversal/skip-subtree/b/c.nix
new file mode 100644
index 000000000000..06216c417be9
--- /dev/null
+++ b/nix/readTree/tests/test-tree-traversal/skip-subtree/b/c.nix
@@ -0,0 +1,3 @@
+{ ... }:
+
+"cool"
diff --git a/nix/readTree/tests/test-tree-traversal/skip-subtree/default.nix b/nix/readTree/tests/test-tree-traversal/skip-subtree/default.nix
new file mode 100644
index 000000000000..3d9f241cddb5
--- /dev/null
+++ b/nix/readTree/tests/test-tree-traversal/skip-subtree/default.nix
@@ -0,0 +1,5 @@
+{ ... }:
+
+{
+  but = "the default.nix is still read";
+}