manager: Add unit test cases

The tests cover the methods of `conv` mod, `FsManager`, and
`SystemdManager`. Since we have to manipulate the cgroups during testing,
the tests related to this part are set to be run in sequence.

Signed-off-by: Xuewei Niu <[email protected]>

Author: justxuewei

Cargo.toml

@@ -24,6 +24,7 @@ bit-vec = "0.6"
 [dev-dependencies]
 libc = "0.2.76"
 rand = "0.8"
+nix = "0.25"
 
 [features]
 default = []

Makefile

@@ -19,10 +19,14 @@ build: debug
 # Tests and linters
 #
 
-.PHONY: test
-test: test-systemd
-	cargo test -- --color always --nocapture \
-	  --skip systemd::dbus::client::tests
+# Tests that manipulate cgroups should run in sequence, so that
+# `--test-threads=1` is used.
+test: test-systemd test-fs-manager test-systemd-manager
+	cargo test --all-features -- --color always \
+	  --nocapture \
+	  --skip systemd::dbus::client::tests \
+	  --skip manager::fs::tests \
+	  --skip manager::systemd::tests
 
 .PHONY: test-systemd
 # Tests that manipulate cgroups should run in sequence, so that
@@ -33,6 +37,20 @@ test-systemd:
 	    --color always --nocapture \
 		--test-threads=1
 
+.PHONY: test-fs-manager
+# See test-systemd
+test-fs-manager:
+	cargo test --all-features --package cgroups-rs \
+		--lib -- manager::fs::tests \
+		--color always --nocapture --test-threads=1
+
+.PHONY: test-systemd-manager
+# See test-systemd
+test-systemd-manager:
+	cargo test --all-features --package cgroups-rs \
+	  --lib -- manager::systemd::tests \
+	  --color always --nocapture --test-threads=1
+
 .PHONY: check
 check: fmt clippy
 

src/manager/conv.rs

@@ -67,3 +67,47 @@ pub(crate) fn memory_swap_to_cgroup_v2(memswap_limit: i64, mem_limit: i64) -> Re
 
     Ok(memswap_limit - mem_limit)
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::manager::conv::*;
+
+    #[test]
+    fn test_cpu_shares_to_cgroup_v2() {
+        assert_eq!(cpu_shares_to_cgroup_v2(0), 0);
+        assert_eq!(cpu_shares_to_cgroup_v2(1), 1);
+        assert_eq!(cpu_shares_to_cgroup_v2(2), 1);
+        assert_eq!(cpu_shares_to_cgroup_v2(100), 4);
+        assert_eq!(
+            cpu_shares_to_cgroup_v2(CPU_SHARES_V1_MAX),
+            CPU_WEIGHT_V2_MAX
+        );
+        assert_eq!(
+            cpu_shares_to_cgroup_v2(CPU_SHARES_V1_MAX - 1),
+            CPU_WEIGHT_V2_MAX - 1
+        );
+        assert_eq!(cpu_shares_to_cgroup_v2(u64::MAX), CPU_WEIGHT_V2_MAX);
+    }
+
+    #[test]
+    fn test_memory_swap_to_cgroup_v2() {
+        // memory no limit and swap is 0, treat it as no limit
+        assert_eq!(memory_swap_to_cgroup_v2(0, -1).unwrap(), -1);
+        // -1 is "max", 0 is "unset", so treat as is
+        assert_eq!(memory_swap_to_cgroup_v2(-1, 0).unwrap(), -1);
+        assert_eq!(memory_swap_to_cgroup_v2(0, 0).unwrap(), 0);
+
+        // Now swap cannot be 0 or -1
+
+        // Unlimited memory, so treat swap as is.
+        assert_eq!(memory_swap_to_cgroup_v2(100, -1).unwrap(), 100);
+        // Unset or unknown memory, can't calculate swap.
+        assert!(memory_swap_to_cgroup_v2(100, 0).is_err());
+        // Does not make sense to subtract a negative value.
+        assert!(memory_swap_to_cgroup_v2(100, -2).is_err());
+        // Swap + mem < mem
+        assert!(memory_swap_to_cgroup_v2(50, 100).is_err());
+        // Real swap
+        assert_eq!(memory_swap_to_cgroup_v2(200, 100).unwrap(), 100);
+    }
+}