Merge ~adam-collard/maas:seed-info-in-one into maas:master

[Adam Collard]

Report the seed info in an easier to copy format

Before:
```
Python hash seed: {{{3757171038}}}
Random seed: {{{6b4ba8b9ef6d17b3}}}
```

After:
```

Seeds: {{{MAAS_RAND_SEED=6b4ba8b9ef6d17b3 PYTHONHASHSEED=3757171038}}}
```

The latter is copy-pastable for re-running the test

[Alberto Donato (ack)]

nice!

review: Approve

diff --git a/src/maastesting/testcase.py b/src/maastesting/testcase.py
index 9fc82f1..a51cb5e 100644
--- a/src/maastesting/testcase.py
+++ b/src/maastesting/testcase.py
@@ -128,16 +128,19 @@ class MAASTestCase(
         if "MAAS_DATA" in os.environ:
             self.useFixture(MAASDataFixture())
 
-        rand_seed = os.environ.get("MAAS_RAND_SEED", None)
+        rand_seed = os.environ.get("MAAS_RAND_SEED")
         random.seed(rand_seed)
+        seed_info = []
         if rand_seed is not None:
-            self.addDetail("Random seed", text_content(rand_seed))
+            seed_info.append(f"MAAS_RAND_SEED={rand_seed}")
 
         if "PYTHONHASHSEED" in os.environ:
-            self.addDetail(
-                "Python hash seed", text_content(os.environ["PYTHONHASHSEED"])
+            seed_info.append(
+                "PYTHONHASHSEED={}".format(os.environ["PYTHONHASHSEED"])
             )
 
+        if seed_info:
+            self.addDetail("Seeds", text_content(" ".join(seed_info)))
         # Capture Twisted logs and add them as a test detail.
         twistedLog = self.useFixture(TwistedLoggerFixture())
         self.addDetail("Twisted logs", twistedLog.getContent())